text:
\section{Introduction}
\label{sect_intro}

      \begin{figure*}[ht]
   \centering
   \includegraphics[trim = 45mm 5mm 35mm 10mm, clip, width=16.5cm]{Spectrum-03b.eps}
      \caption{Two isomers of vinyl isocyanate and their characteristic features in the room-temperature millimeter wave spectrum. The spectrum reveals compact groups of $a$-type $R$-branch transitions of the \textit{trans} species in the ground state and $v_{18}=1$, $v_{13}=1$, and $v_{18}=2$ excited vibrational states. Weaker $a$-type $R$-branch transitions of the less stable \textit{cis} isomer are at the present scale observed in the form of significantly more diffuse groups.}
      \label{spectrum}
   \end{figure*}

A few isocyanate bearing molecules have been detected in the interstellar medium (ISM).
The simplest one, isocyanate radical (NCO), has been observed relatively recently in the line survey of L483 \citep{Marcelino2018},
while isocyanic acid (HNCO) belongs among the early molecules detected in the universe dating back to 1972 \citep{Snyder1972,Buhl1972}. HNCO is a well established interstellar molecule observed in the direction of a variety of sources such as TMC-1 \citep{Brown1981}, IRAS~16293-2422 \citep{Bisschop2008,Coutens2016}, L483 \citep{Marcelino2018}, NGC~6334I \citep{Ligterink2020}, G31.41+0.31 \citep{Colzi2021}, Serpens~SMM1 \citep{Ligterink2021}, and G331.512-0.103 \citep{Canelo2021}.
Its protonated form, H$_2$NCO$^+$, had been tentatively observed in Sgr~B2 by \cite{Gupta2013}, but later on its presence in space has been confirmed by \cite{Marcelino2018}.
H$_2$NCO$^+$ has been recently detected toward the molecular cloud G+0.693-0.027 \citep{Rodriguez-Almeida21}
where NCO, cyanogen isocyanate (NCNCO), and ethynyl isocyanate (HCCNCO) were also searched for.
Methyl derivative of HNCO, methyl isocyanate (CH$_3$NCO), has been first detected in the Sgr~B2(N) and Orion~KL star-forming regions \citep{Halfen15,Cernicharo16,Belloche17}. Further observations have shown that it is also present in other sources such as IRAS~16293-2422 \citep{Ligterink17,Martin-Domenech2017}, G31.41+0.31 \citep{Gorai2021,Colzi2021}, Serpens~SMM1 \citep{Ligterink2021}, G10.47+0.03 \citep{Gorai2020}, G+0.693-0.027 \citep{Zeng2018}, and G328.2551-0.5321 \citep{Csengeri2019}. Very recently, the even more complex ethyl isocyanate (C$_2$H$_5$NCO) has been discovered toward the G+0.693-0.027 molecular cloud by \cite{Rodriguez-Almeida21}. Isocyanates are therefore quite widespread across the Galaxy and more such species might be detected in future. In addition, new molecular discoveries are reinforced by increasing the sensitivity and detector bandwidths of astronomical observing capabilities \citep{Jorgensen2020,Tercero2021} as demonstrated by some of the latest astronomical detections \citep{Cernicharo2021,Rivilla2021,McCarthy2021} which contributed to the recent huge jump in the total number of detected compounds \citep{McGuire2022}.

The aforementioned discoveries opened unique possibilities to uncover the fundamentals of the chemistry of isocyanates in space and their possible role as precursors in the formation of other compounds \citep{Majumdar2017,Zeng2018}. For example, H$_2$NCO$^+$ has been considered as a candidate reactant partner of HC$_3$N in the synthesis of nucleobases \citep{Choe2021} and CH$_3$NCO as a precursor for the synthesis of  N-methylformamide (CH$_3$NHCHO, \citealt{Belloche17}). The latter has been observed toward Sgr~B2 and NGC~6334I star-forming regions \citep{Belloche17,Belloche19,Ligterink2020} and very recently also toward the hot core G31.41+0.31 \citep{Colzi2021}. This possible link with prebiotic chemistry further increases an interest in isocyanates as targets for laboratory spectroscopic studies in view of future observations.

In the present work, the molecule in question is vinyl isocyanate (C$_2$H$_3$NCO),
the most thermodynamically stable isomer with a C$_3$H$_3$NO formula \citep{Fourre2020}.
It is more complex than CH$_3$NCO and at the same time it contains two hydrogen atoms fewer than recently detected C$_2$H$_5$NCO. In addition, it bears in its backbone the vinyl functional group which is a common structural motif in several other interstellar compounds such as vinyl cyanide \citep[C$_2$H$_3$CN;][]{Gardner1975}, vinylacetylene \citep[C$_2$H$_3$CCH;][]{Cernicharo2021c}, vinylcyanoacetylene \citep[C$_2$H$_3$C$_{3}$N;][]{Kelvin_Lee_2021}, and vinylamine \citep[C$_2$H$_3$NH$_{2}$;][]{Zeng2021}. A search for vinyl isocyanate in the line survey of the G+0.693-0.027 molecular cloud has been reported very recently \citep{Rodriguez-Almeida21} on the basis of the only rotational spectrum reported so far below 40~GHz \citep{Bouchy1977,Kirby1978,Bouchy1979}. On the other hand, no such trials have been performed in the millimeter wave surveys of other interstellar sources very likely due to the lack of laboratory information in the millimeter wave spectral region.

The aim of the present work is therefore two-fold. First, we want to extend the laboratory rotational spectrum of vinyl isocyanate up to 330 GHz and analyze the ground state rotational transitions of its two stable planar forms: \textit{trans} and \textit{cis} (see Fig. \ref{spectrum}). The latter has been found by \cite{Kirby1978} to be less stable by 4.99(24)~kJ~mol$^{-1}$ or 417(20)~cm$^{-1}$ or 600(29)~K, where the numbers in parentheses represent uncertainties in units of the last decimal digits.
These new measurements and analyses then lay a foundation to accomplish a search for interstellar signatures of vinyl isocyanate by millimeter wave astronomy.
We target the high-mass star-forming region Sgr B2(N) which reveals an astonishingly rich collection of molecular species, including isocyanates.

\begin{table*}
\caption{Spectroscopic constants for the \textit{trans} and \textit{cis} isomers of vinyl isocyanate in their ground vibrational states ($A$-reduction, I$^{\text{r}}$-representation) in comparison with previously published results and quantum-chemical calculations.}
\label{constants}
\begin{center}
\begin{footnotesize}
\setlength{\tabcolsep}{6.0pt}
\begin{tabular}{ l r r r r r r r}
\hline\hline
\vspace{-0.3cm}\\
 & \multicolumn{3}{c}{\textit{Trans}} &  & \multicolumn{3}{c}{\textit{Cis}}  \\
\cline{2-4}
\cline{6-8}
\vspace{-0.2cm}\\
 &  This work  & \cite{Kirby1978} &  Calculated\tablefootmark{a} &   &  This work  & \cite{Kirby1978} &  Calculated\tablefootmark{a} \\
\hline
\vspace{-0.2cm}\\
$A            $  /MHz             & 62586.3098 (25)\tablefootmark{b}  & 62584.051 (35) &   62314.45     &  &  20144.090 (41)         &  20146.8 (10)    &  20193.42     \\
$B            $  /MHz                       &      2437.747011 (86)   &   2437.730 (3) &    2438.70     &  &   3107.45256 (44)       &   3107.267 (20)  &  3096.35      \\
$C            $  /MHz                       &      2346.477545 (88)   &   2346.507 (1) &    2346.96     &  &   2689.42677 (34)       &   2689.513 (25)  &  2682.28      \\
$\mathit{\Delta_{J}}   $  /kHz                       &         0.266716 (35)   &    0.321 (9)   &   0.2695       &  &      3.03750 (13)       &  2.23 (26)       &   3.078       \\
$\mathit{\Delta_{JK}}  $  /kHz                       &      --14.3999 (20)     &    --14.30 (7) &  --18.48       &  &   --80.8627 (28)        & --80.26 (71)     & --80.49       \\
$\mathit{\Delta_{K}}   $  /kHz                       &      2270.62 (24)       &      ...       &   2343         &  &    841.7 (15)           &     ...          &   780.0       \\
$\delta_{J}   $  /kHz                       &         0.0182857 (54)  &      ...       &  0.02243       &  &      0.830560 (99)      &     ...          &  0.8380       \\
$\delta_{K}   $  /kHz                       &        10.3755 (90)     &      ...       &  8.657         &  &     13.792 (22)         &     ...          &  11.62        \\
$\mathit{\Phi_{J}}     $  /Hz                        &      0.0002564 (41)     &      ...       &  0.0002777     &  &      0.008427 (26)      &     ...          &  0.009854     \\
$\mathit{\Phi_{JK}}    $  /Hz                        &    --0.04791 (43)       &      ...       & --0.07105      &  &      0.2450 (49)        &     ...          &  0.2170       \\
$\mathit{\Phi_{KJ}}    $  /Hz                        &    --2.129 (69)         &      ...       & --2.487        &  &   --14.050 (32)         &     ...          & --12.44       \\
$\mathit{\Phi_{K}}     $  /Hz                     & --471.8\tablefootmark{c}   &      ...       &   --471.8      &  &     289 (24)            &     ...          &  130.8        \\
$\phi_{J}     $  /mHz                        &      0.03926 (87)    &      ...       &  0.06060    &  &      3.583 (16)      &     ...          &  4.221     \\
$\phi_{JK}    $  /Hz                        &      0.0311 (20)        &      ...       &   0.01395      &  &    --0.0271 (43)        &     ...          &  0.01708      \\
$\phi_{K}     $  /Hz                    & 21.58\tablefootmark{c}      &      ...       &  21.58         &  &     12.40 (36)          &     ...          &   10.60       \\
$  L_{JK}     $  /mHz                       &         ...             &      ...       &     ...        &  &   --0.16472 (85)        &     ...          &   ...         \\
$ L_{KKJ}     $  /mHz                       &         ...             &      ...       &     ...        &  &     5.267 (96)          &     ...          &   ...         \\
$ P_{KKKJ}    $  /mHz                       &         ...             &      ...       &     ...        &  &   --0.00169 (11)        &     ...          &   ...         \\

$\Delta E_{\text{ZPE}} $\tablefootmark{d}  /cm$^{-1}$  &  ...         &      ...       &     0          &  &         ...             &     417 (20)     &   301          \\
$J_{\text{min}}/J_{\text{max}}$             &     4 / 80              &      4 / 19    &     ...        &  &  1 / 61  &  4 / 6  & ... \\
$K_{a}^{\text{min}}/K_{a}^{\text{max}}$     &     0 / 7               &      0 / 7     &     ...        &  &  0 / 21  &  0 / 5  & ... \\
$N$\tablefootmark{e}                        &     464                 &       30       &     ...        &  &  608     &   18    & ... \\
$\sigma_{\text{fit}}$\tablefootmark{f}/MHz  &     0.024               &      ...       &     ...        &  &  0.030   &   ...   & ... \\
$\sigma_{\text{w}}$\tablefootmark{g}        &     0.90                &      ...       &     ...        &  &  0.88    &   ...   & ... \\
\hline
\end{tabular}
\end{footnotesize}
\end{center}
\tablefoot{
\tablefoottext{a}{Calculated at CCSD/cc-pVTZ level of theory.}
\tablefoottext{b}{The numbers in parentheses are the parameter uncertainties in units of the last decimal digits. Their values are close to 1$\sigma$ standard uncertainties (67\% confidence level) because the unitless (weighted) deviation of the fit is close to 1.0. SPFIT/SPCAT program package \citep{Pickett1991} was used for the analysis.}
\tablefoottext{c}{Fixed to the calculated value, which is usually a preferred constraint over the zero or poorly determined value \citep{Urban1990,Koucky2013}.}
\tablefoottext{d}{Relative energy with respect to the global minimum, taking into account the zero-point energy (ZPE).}
\tablefoottext{e}{Number of distinct frequency lines in the fit.}
\tablefoottext{f}{Root mean square deviation of the fit.}
\tablefoottext{g}{Unitless (weighted) deviation of the fit.}}
\end{table*}

\section{Experimental details}
{\label{s:experiments}}

\subsection{Synthesis}

The sample of vinyl isocyanate was prepared by Curtius rearrangement of acryloyl azide under vacuum (0.1~mbar) using a modified synthesis of \cite{Kirby1978}.
Briefly, sodium azide NaN$_{3}$ (3.25~g, 50~mmol) was mixed with 30~mL of diethylene glycol dibutyl ether in a three-necked flask equipped
with a magnetic stirring bar and a stopcock. The flask was evacuated to a pressure of about 0.1~mbar. Keeping the stopcock closed, the flask was immersed in a bath at --20~$^{\circ}$C. In the next step, acryloyl chloride (2.85~g, 31~mmol) was added in five portions (5 x 500~$\mu$L) through a septum. The mixture was stirred for two hours at 0~$^{\circ}$C allowing
the formation of acryloyl azide. The stopcock was then opened and all volatiles passed into the vacuum line containing a quartz tube in an oven heated approximately to 500~$^{\circ}$C and two successive cold U-tubes. The first U-tube was immersed in a bath at --70~$^{\circ}$C to remove impurities and the second one in liquid nitrogen bath to collect
vinyl isocyanate. The final product was used without any further purification. The main advantage of this experimental procedure was to avoid isolation of the potentially explosive acryloyl azide.

\subsection{Spectroscopic measurements}

The rotational spectrum of vinyl isocyanate was recorded in the frequency regions 127.5--218 and 282--330~GHz using the upgraded Prague semiconductor millimeter wave spectrometer. The spectrometer is based on a sequential multiplication of the fundamental synthesizer frequency (lower than 50 GHz) by a set of active and passive multipliers and a phase-sensitive detection as described in \cite{Kania2006}. The 2.8 and 2.3 meters long Pyrex glass free-space cells were used for the measurements. The optical path lengths were doubled to 5.6 and 4.6~m by roof-top mirrors. The millimeter-wave radiation was modulated at the modulation frequency of 28 kHz
and the detected signal was demodulated by means of a lock-in amplifier working at twice the modulation frequency.
All spectra were registered by upward and downward frequency scanning and averaged. The sample was kept at room temperature and a pressure of around 20~$\mu$bar during the experiments.

\section{Quantum-chemical calculations}
{\label{s:theory}}

Although vinyl isocyanate has been the subject of some computational studies \citep{Badawi2001,Olsen1979}, we have undertaken our own calculations
in order to obtain a reasonable estimation for the spectroscopic parameters relevant to this work.
We used coupled-cluster approximation on the level of coupled-cluster-single-double (CCSD) model \citep{ccsd}
as it is implemented in CFOUR program package \citep{cfour}, in conjunction with Dunning's correlation consistent triple-$\zeta$ (cc-pVTZ) basis set \citep{Dunning1989}.
The convergence criteria for the HF-SCF equations, the CC amplitude equations and
the linear equations were set to 10$^{-8}$ atomic units.
This means the convergence structure calculations and the analytical second derivatives were followed by finite difference techniques to obtain the full
cubic force field. These harmonic and anharmonic force field calculations yielded the rotational and centrifugal distortion constants listed in Table \ref{constants} together
with the energy difference between the \textit{cis} and \textit{trans} isomer of 3.6~kJ~mol$^{-1}$ (301~cm$^{-1}$ or 433~K).
The optimized geometries of both species are shown in Fig. \ref{spectrum} and their harmonic and anharmonic vibrational frequencies are provided in Table \ref{vib-modes}.

     \begin{figure}[ht]
   \centering
   \includegraphics[trim = 0mm 20mm 0mm 25mm, clip, width=8.5cm]{K-structure.eps}
      \caption{Perturbations in the ground state rotational spectrum of \textit{trans} vinyl isocyanate.
      The experimental spectrum is compared with predictions based on the analysis up to $K_a=6$.
      All the assigned lines correspond to $a$-type $R$-branch transitions except that marked with a star which is the $b$-type $40_{0,40}\leftarrow 39_{1,39}$ transition. The blue diamond symbols highlight the transitions included in the fit while the red question marks indicate perturbed transitions that could not be confidently assigned.}
      \label{perturbations}
   \end{figure}

\section{Rotational spectra and analyses}
{\label{s:analysis}}

\subsection{Trans isomer}

Since the \textit{trans} isomer represents the most stable species on the potential energy landscape of vinyl isocyanate, it is the most relevant
target for astronomical observations as it presents the strongest lines in the millimeter wave spectrum in Fig. \ref{spectrum}.
The most visible features in the spectrum are compact groups of $a$-type $R$-branch transitions arising from the near-prolate character of the molecule ($\kappa$ = --0.997) and its large dipole moment component along the $a$ principal inertial axis ($|\mu_{a}|=$ 2.047(6)~D and $|\mu_{b}| =$ 0.824(9)~D from \citealt{Kirby1978}).
The analysis was commenced by refitting the data set from \cite{Kirby1978} and generating spectral line predictions.
The predicted transitions were searched for with the help of the Loomis-Wood-type plot technique \citep{LW} implemented in our own program \citep{Vavra2020}.
The program is written in the Matlab software \citep{MATLAB:2020} and allows for the line assignments to quantum numbers, precise determination of the line frequencies employing the Voight profile function, and saving the data in a line list among other features. It generates input files for the SPFIT/SPCAT program package \citep{Pickett1991} which is executed directly from the user interface, allowing a straightforward analysis of the assigned lines. On this basis, we easily expanded the assignments for $K_{a}=$ 0--6 transitions up to $J = 69$ and identified weak $b$-type $R$-branch and $Q$-branch transitions.

Difficulties were encountered in assignments and fitting $K_{a}\geq 7$ transitions. In the absence of perturbations, these transitions are expected to progressively run to higher frequencies as shown in the lower panel of Fig. \ref{perturbations}. Instead, we observed irregular shifts with respect to their predicted positions that could not be treated within the scope of classical semi-rigid rotor Hamiltonian.
Some of these transitions even could not be confidently assigned (see Fig. \ref{perturbations}).
Consequently, we limited the analysis of $a$-type $R$-branch transitions to $K_{a}=6$.
These transitions were merged with $b$-type $R$-branch and $Q$-branch transitions which, due to low intensities and the large value of the $A$ rotational constant, were limited to $K_{a}=3$ and $J=80$.
Our data set was finally combined with microwave transitions from \cite{Kirby1978} and analyzed using Watson's $A$-reduced Hamiltonian in I$^{\text{r}}$-representation \citep{Watson1977} with terms up to the sixth power in the angular momentum. The only exceptions were $\Phi_K$ and $\phi_K$ which were fixed at the values estimated from quantum-chemical calculations. We note that all transitions from \cite{Kirby1978} were found to be fully consistent with our measurements and could be perfectly fitted. Results from this joint analysis are provided in Table \ref{constants} and the list of measured transitions in Table \ref{transitions-trans}. Watson's $S$-reduced Hamiltonian led to results of similar quality.
The origin of perturbations in the rotational spectrum of \textit{trans} vinyl isocyanate is further discussed in Sect. \ref{ss:lab}.

\begin{table*}
\caption{Partition functions and abundances for the two isomers of vinyl isocyanate.}
\label{part-fce}
\begin{center}
\begin{footnotesize}
\setlength{\tabcolsep}{7.0pt}
\begin{tabular}{ r r r r r r r r r r r}
\hline\hline
\vspace{-0.3cm}\\
   &  \multicolumn{3}{c}{\textit{Trans} isomer} & & \multicolumn{3}{c}{\textit{Cis} isomer} & & & \\
\cline{2-4}
\cline{6-8}
\vspace{-0.3cm}\\
$T$ (K) &  $Q_{\text{rot}}$ & $Q_{\text{vib}}$ & (\%)\tablefootmark{a} & & $Q_{\text{rot}}$\tablefootmark{b} & $Q_{\text{vib}}$ & (\%) & & $Q_{\text{rot}}^{trans+cis}$ & $Q_{\text{vib}}^{trans+cis}$ \\
\vspace{-0.3cm}\\
\hline
\vspace{-0.3cm}\\
   300.000             &   46450.52  &  9.03          &  74          &  &  16049.82   &  9.22          &  26         & & 62500.34  &  9.08  \\
   225.000             &   30146.59  &  4.89          &  82          &  &   6435.09   &  5.00          &  18         & &  36581.68  &  4.91  \\
   150.000             &   16397.84  &  2.65          &  92          &  &   1336.05   &  2.69          &   8         & &  17733.89  &  2.65  \\
    75.000             &    5794.43           &  1.39          & 100          &  &     26.29   &  1.38          &   0         & &    5820.71  &  1.39  \\
    37.500             &    2048.88           &  1.06          & 100          &  &      0.03            &  1.05          &   0         & &     2048.91          &      1.06           \\
    18.750             &     724.98           &  1.00          & 100          &  &      0.00            &  1.00          &   0         & &     724.98           &      1.00           \\
     9.375             &     256.81           &  1.00          & 100          &  &      0.00            &  1.00          &   0         & &     256.81           &      1.00           \\
     5.000    &     100.37  &  1.00 & 100 &  &      0.00   &  1.00 &   0& &     100.37  &      1.00  \\
     2.725    &     40.65  &  1.00 & 100 &  &      0.00   &  1.00 &   0& &     40.65  &      1.00  \\
\hline
\end{tabular}
\end{footnotesize}
\end{center}
\tablefoot{
\tablefoottext{a}{Isomer abundance calculated as $Q_{\text{tot}}^{\mathit{trans}}/Q_{\text{tot}}^{\mathit{trans+cis}}$ where $Q_{\text{tot}}=Q_{\text{rot}}\times Q_{\text{vib}}$.}
\tablefoottext{b}{Corrected for the energy difference between the \textit{trans} and \textit{cis} isomer, i.e. the $0_{0,0}$ level is set to 301~cm$^{-1}$.}
}

\end{table*}

\begin{table*}[!ht]
 \begin{center}
 \caption{
 Parameters of our best-fit LTE model of methyl isocyanate toward Sgr~B2(N1S) and upper limits for ethyl isocyanate and vinyl isocyanate.
}
 \label{t:coldens}
 \vspace*{-1.2ex}
 \begin{tabular}{lcrccccccr}
 \hline\hline
 \multicolumn{1}{c}{Molecule} & \multicolumn{1}{c}{Status\tablefootmark{a}} & \multicolumn{1}{c}{$N_{\rm det}$\tablefootmark{b}} & \multicolumn{1}{c}{Size\tablefootmark{c}} & \multicolumn{1}{c}{$T_{\mathrm{rot}}$\tablefootmark{d}} & \multicolumn{1}{c}{$N$\tablefootmark{e}} & \multicolumn{1}{c}{$F_{\rm vib}$\tablefootmark{f}} & \multicolumn{1}{c}{$\Delta V$\tablefootmark{g}} & \multicolumn{1}{c}{$V_{\mathrm{off}}$\tablefootmark{h}} & \multicolumn{1}{c}{$\frac{N_{\rm ref}}{N}$\tablefootmark{i}} \\
  & & & \multicolumn{1}{c}{\small ($''$)} & \multicolumn{1}{c}{\small (K)} & \multicolumn{1}{c}{\small (cm$^{-2}$)} & & \multicolumn{1}{c}{\small (km~s$^{-1}$)} & \multicolumn{1}{c}{\small (km~s$^{-1}$)} & \\
 \hline
 CH$_3$NCO\tablefootmark{(j)}$^\star$ & d & 51 &  2.0 &  200 &  2.5 (17) & 1.00 & 5.0 & 0.0 &       1 \\
\hline
 C$_2$H$_5$NCO, $\varv=0$ & n & 0 &  2.0 &  200 & $<$  8.1 (16) & 10.1 & 5.0 & 0.0 & $>$     3.1 \\
 \hspace*{10ex} $\varv_{\rm t}=1$ & n & 0 &  2.0 &  200 & $<$  8.1 (16) & 10.1 & 5.0 & 0.0 & $>$     3.1 \\
\hline
 \textit{trans}-C$_2$H$_3$NCO, $\varv=0$ & n & 0 &  2.0 &  200 & $<$  2.4 (16) & 4.00 & 5.0 & 0.0 & $>$      11 \\
 \textit{cis}-C$_2$H$_3$NCO, $\varv=0$ & n & 0 &  2.0 &  200 & $<$  5.0 (17) & 4.00 & 5.0 & 0.0 & $>$    0.50 \\
\hline
 \end{tabular}
 \end{center}
 \vspace*{-2.5ex}
 \tablefoot{
 \tablefoottext{a}{d: detection, n: nondetection.}
 \tablefoottext{b}{Number of detected lines \citep[conservative estimate, see Sect.~3 of][]{Belloche16}. One line of a given species may mean a group of transitions of that species that are blended together.}
 \tablefoottext{c}{Source diameter (\textit{FWHM}).}
 \tablefoottext{d}{Rotational temperature.}
 \tablefoottext{e}{Total column density of the molecule. $x$ ($y$) means $x \times 10^y$.}
 \tablefoottext{f}{Correction factor that was applied to the column density to account for the contribution of vibrationally excited states, in the cases where this contribution was not included in the partition function of the spectroscopic predictions.}
 \tablefoottext{g}{Linewidth (\textit{FWHM}).}
 \tablefoottext{h}{Velocity offset with respect to the assumed systemic velocity of Sgr~B2(N1S), $V_{\mathrm{sys}} = 62$ km~s$^{-1}$.}
 \tablefoottext{i}{Column density ratio, with $N_{\rm ref}$ the column density of the previous reference species marked with a $\star$.}
 \tablefoottext{j}{The parameters were derived from the ReMoCA survey by \citet{Belloche19}.}
 }
 \end{table*}

\subsection{Cis isomer}

The spectroscopic constants from \cite{Kirby1978} were used for the first prediction of the rotational spectrum of \textit{cis} vinyl isocyanate in the millimeter wave region.
Only $a$-type $R$-branch transitions were observed for this isomer in agreement with the dipole moment components of $|\mu_{a}|=$ 2.14~(2)~D and $|\mu_{b}| =$~0.09~(2)~D as determined by Stark spectroscopy \citep{Bouchy1979}.
It was possible to identify and iteratively fit the rotational transitions up to $J=61$ and $K_a=21$.
We were not able to assign the transitions with higher values of $K_a$ because of their low intensities, which caused them to disappear in the spectral confusion,"weeds", of lines from the most stable \textit{trans} isomer.
Our data set was combined with low-frequency transitions from \cite{Kirby1978} and \cite{Bouchy1977} and was
fit to matrix elements of Watson's $A$-reduced effective rotational Hamiltonian \citep{Watson1977}. Some transitions from previous microwave works revealed larger residuals.
Larger uncertainties were thus assigned to these transitions and four of them were excluded from the fit.
The complete list of treated transitions is provided in Table \ref{transitions-cis}.
and the molecular constants determined from the analysis are reported in Table~\ref{constants}.

\begin{figure*}
\centerline{\resizebox{0.75\hsize}{!}{\includegraphics[angle=0]{c2h3nco-t_ve0_n1s_1.eps}}}
\caption{Transitions of vinyl isocyanate \textit{trans}-C$_2$H$_3$NCO covered
by the ReMoCA survey. The LTE synthetic spectrum used to derive the upper limit
on the column density of \textit{trans}-C$_2$H$_3$NCO, $\varv = 0$ is
displayed in red and overlaid on the observed spectrum of Sgr~B2(N1S) shown in
black. The blue synthetic spectrum contains the contributions of all molecules
identified in our survey so far, but does not include the contribution of the
species shown in red. The central frequency is indicated in MHz below each
panel as well as the half-power beam width on the left, the width of each
panel in MHz in parentheses, and the continuum level of the
baseline-subtracted spectra in K in brackets. The y-axis is labeled in
brightness temperature units (K). The dotted line indicates the $3\sigma$
noise level. The figure only shows the transitions of \textit{trans}-C$_2$H$_3$NCO for which the red
synthetic spectrum has a significant peak temperature (compared to the noise
level) and which are not too heavily blended with much stronger emission of
other molecules.}
\label{f:spec_c2h3nco-t_ve0}
\end{figure*}

\subsection{Partition functions}

The spectroscopic constants from Table \ref{constants} were used to evaluate the rotational partition function ($Q_{\text{rot}}$) for both isomers.
We used the SPCAT program \citep{Pickett1991} to undertake the numerical summation over the ground state energy levels up to $J=240$ and $K_{a}=46$ for the \textit{trans} isomer and $J=210$ and $K_{a}=72$ for the \textit{cis} isomer. In addition, for the \textit{cis} form, this summation was corrected for the energy difference between the \textit{cis} and \textit{trans} form.
We used $\Delta E_{\text{ZPE}}=301$~cm$^{-1}$ from our quantum-chemical calculations. This value reproduces quite well the experimental intensities of the \textit{cis} isomer lines with respect to neighboring lines of the \textit{trans} isomer in our spectrum. On the other hand, the experimental value 417(20)~cm$^{-1}$ from \cite{Kirby1978} underestimates these \textit{cis} isomer lines relative intensities.
For this reason we consider our calculated value for the energy difference as more reliable.
Obtained rotational partition functions at nine different temperatures are provided in Table \ref{part-fce}. Their values represent the individual contributions from the \textit{trans} and \textit{cis} isomer to the rotational partition function of the molecule as a whole which is also given in Table \ref{part-fce}.
For completeness, we provide in Table \ref{part-fce-cisE0} the rotational partition functions of the \textit{cis} isomer also as a separate species, i.e. with the $0_{0,0}$ level set to 0~cm$^{-1}$.
The vibrational partition functions ($Q_{\text{vib}}$) were estimated using Eq. 3.60 of \cite{Gordy1970} by taking into account the anharmonic frequencies of the eighteen normal vibrational modes from Table~\ref{vib-modes} and are listed in Table \ref{part-fce}.
The same table also shows that the \textit{cis} isomer represents an important fraction of the room-temperature population of
vinyl isocyanate while its abundance is estimated to only 8~\% at 150~K.

\begin{figure*}
\centerline{\resizebox{0.75\hsize}{!}{\includegraphics[angle=0]{c2h3nco-c_ve0_n1s_1.eps}}}
\caption{Same as Fig.~\ref{f:spec_c2h3nco-t_ve0} but for
\textit{cis}-C$_2$H$_3$NCO, $\varv$~=~0.}
\label{f:spec_c2h3nco-c_ve0}
\end{figure*}

\begin{figure*}
\centerline{\resizebox{0.75\hsize}{!}{\includegraphics[angle=0]{c2h5nco_ve0_n1s_1.eps}}}
\caption{Same as Fig.~\ref{f:spec_c2h3nco-t_ve0} but for C$_2$H$_5$NCO,
$\varv$~=~0.}
\label{f:spec_c2h5nco_ve0}
\end{figure*}

\section{Search for vinyl isocyanate toward Sgr~B2(N1)}
\label{s:astro}

\subsection{Observations}
\label{ss:obs_remoca}

The imaging spectral line survey Reexploring Molecular Complexity with ALMA
(ReMoCA) was performed toward the high-mass star forming protocluster
Sgr~B2(N) with the Atacama Large Millimeter/submillimeter Array (ALMA). A
detailed description of the observations and data reduction can be found in
\citet{Belloche19}. We summarize the main features of the survey here. The
phase center is located at the equatorial position
($\alpha, \delta$)$_{\rm J2000}$=
($17^{\rm h}47^{\rm m}19{\fs}87, -28^\circ22'16{\farcs}0$) which is halfway
between the two hot molecular cores Sgr~B2(N1) and Sgr~B2(N2). We defined five
frequency tunings to cover the frequency range from 84.1~GHz to
114.4~GHz with a spectral resolution of 488~kHz (1.7 to 1.3~km~s$^{-1}$).
The survey has a sensitivity per spectral channel that varies
between 0.35~mJy~beam$^{-1}$ and 1.1~mJy~beam$^{-1}$ (rms) depending on the
setup, with a median value of 0.8~mJy~beam$^{-1}$. The angular resolution
(HPBW) ranges from $\sim$0.3$\arcsec$ to $\sim$0.8$\arcsec$ with a median
value of 0.6$\arcsec$ that corresponds to $\sim$4900~au at the distance
of Sgr~B2 \citep[8.2~kpc,][]{Reid19}. An improved version of the
data reduction as described in \citet{Melosso20} was used for this work.
A detailed description of the procedure that was followed to subtract the
continuum emission can be found in Sect. 2.2 of \citet{Belloche19},
complemented by Sect. 4.1 of \citet{Melosso20}. It is difficult to estimate
the uncertainty on the subtracted continuum level in a robust way because of
spectral confusion. From our experience in modeling the line spectra of the
ReMoCA survey, we believe that this uncertainty may be in some cases on the
same order as the noise level itself. We emphasize however that our continuum
subtraction procedure is applied to each spectral window of 1.8~GHz width as a
whole, therefore it is not affected by spectral confusion that arises at
scales of tens or hundreds of MHz.

\begin{figure*}
\centerline{\resizebox{0.75\hsize}{!}{\includegraphics[angle=0]{c2h5nco_ve1_n1s_1.eps}}}
\caption{Same as Fig.~\ref{f:spec_c2h3nco-t_ve0} but for C$_2$H$_5$NCO,
$\varv_{\rm t}$~=~1.}
\label{f:spec_c2h5nco_ve1}
\end{figure*}

We analyzed the spectrum obtained toward the position Sgr~B2(N1S) at
($\alpha, \delta$)$_{\rm J2000}$=
($17^{\rm h}47^{\rm m}19{\fs}870$, $-28^\circ22\arcmin19{\farcs}48$) following the
strategy employed by \citet{Belloche19}. This position is offset by about
1$\arcsec$ to the south of the main hot core Sgr~B2(N1) and has a lower
continuum opacity compared to the peak of the hot core. We assumed local
thermodynamic equilibrium (LTE) and produced synthetic spectra with the
astronomical software Weeds \citep[][]{Maret11} in order to analyze the
observed spectrum. The LTE assumption is justified by the high
densities of the regions where hot-core emission is detected in Sgr~B2(N)
\citep[$>1 \times 10^{7}$~cm$^{-3}$, see][]{Bonfand19}.
We derived a best-fit synthetic spectrum for each molecule separately, and
then added the contributions of all identified molecules together. We used a
set of five parameters to model the contribution of each species: size of the
emitting region
($\theta_{\rm s}$), column density ($N$), temperature ($T_{\rm rot}$), linewidth
($\Delta V$), and velocity offset ($V_{\rm off}$) with respect to the assumed
systemic velocity of the source, $V_{\rm sys}=62$~km~s$^{-1}$.
For nondetected species, the
synthetic spectra that were used to derive their column density upper limits
(red spectra in the figures) are conservative in the sense that they have
synthetic peak temperatures that are sometimes somewhat higher than the
3$\sigma$ noise level (dotted lines in the figures) or slightly above the
signals detected by ALMA (black spectra in the figures), implicitly accounting
for the additional (uncertain) uncertainty that affects the baseline level. In
this way, we are confident that the upper limits do not underestimate the
actual column densities of the nondetected species. For molecules that are detected (see, e.g., \citealt{Belloche19}), the
emission size is measured with Gaussian fits to the integrated intensity maps
of their uncontaminated transitions. The velocity offset and velocity width
are determined directly from the individual line profiles. The rotation
temperature is estimated from a population diagram. Finally, the only
remaining free parameter, the column density, is adjusted manually until a
good visual match between the synthetic and observed spectra is obtained. For
an undetected species, the first four parameters are fixed to values obtained
for a related species and the column density is varied until discrepancies at
the $\sim$3$\sigma$ level appear between the synthetic and observed spectra.
This yields the column density upper limit of the undetected species.

\subsection{Nondetection of vinyl isocyanate}
\label{ss:nondetection_remoca}

In order to search for vinyl isocyanate, C$_2$H$_3$NCO, toward Sgr~B2(N1S),
we relied on the LTE parameters derived for methyl isocyanate, CH$_3$NCO,
toward the same source by \citet{Belloche19} with the ReMoCA survey. These
parameters are listed in Table~\ref{t:coldens}. Assuming that the more complex
molecule vinyl isocyanate traces the same region as methyl isocyanate, we
produced LTE synthetic spectra for the former species adopting the same
parameters as for the latter with only the column density left as a free
parameter. We employed the spectroscopic predictions derived for the
\textit{trans} and \textit{cis} isomers of vinyl isocyanate in
Sect.~\ref{s:analysis} to compute their LTE synthetic spectra. None of these
conformers is detected toward Sgr~B2(N1S), as illustrated in
Figs.~\ref{f:spec_c2h3nco-t_ve0} and \ref{f:spec_c2h3nco-c_ve0}. The upper
limit on the total column density of vinyl isocyanate derived from each
conformer is reported in Table~\ref{t:coldens},
after accounting for the vibrational partition function $Q_{\rm
vib}^{trans+cis}$ provided in Sect.~\ref{s:analysis}.

We also report in Table~\ref{t:coldens} the column density upper limit that we
obtained with the ReMoCA survey for ethyl isocyanate, C$_2$H$_5$NCO. The
nondetection of this molecule, both in its torsional ground state and its
first torsionally excited state, is illustrated in
Figs.~\ref{f:spec_c2h5nco_ve0} and \ref{f:spec_c2h5nco_ve1}, respectively.
We employed the spectroscopic entry 71508 (version 1) of the Cologne Database
for Molecular Spectroscopy\footnote{https://cdms.astro.uni-koeln.de/}
\citep[CDMS,][]{Mueller05} to compute the LTE synthetic spectra of the
torsional ground state used to derive the upper limit to the column density of
ethyl isocyanate. This CDMS entry is mainly based on the measurements reported
in \citet{Kolesnikova18}. For the first torsionally excited state, we used
spectroscopic predictions from \citet{Kolesnikova18} prepared in electronic
format by one of us. The upper limit given in Table~\ref{t:coldens} accounts
for the (substantial) vibrational correction that was estimated using the
energies of the vibrational modes derived by \citet{Durig10} for ethyl
isocyanate. This upper limit holds under the assumption that a single conformation
exists for this species. A single form with quite a large number of molecules
in excited torsional states is suggested from the room-temperature microwave
and millimeter wave spectroscopy of gas phase samples \citep{Sakaizumi1976,Kolesnikova18}. Infrared spectroscopic data of
ethyl isocyanate dissolved in liquid noble gases were, on the other hand, interpreted
as a mixture of the \textit{cis} and \textit{trans} forms on the basis of quantum-chemical calculations \citep{Durig10}.
These calculations are, however, strongly dependent on the basis set used and
predict very low barrier for the conformational interchange which could even
fall into a calculation error.

The most stringent constraint on the column density of vinyl isocyanate is
obtained from its \textit{trans} conformer. We find that vinyl isocyanate is
at least 11 times less abundant than methyl isocyanate toward Sgr B2(N1S).
This is a factor $\sim$2 less stringent than the limit found on the basis of
the \textit{trans} conformer of vinyl isocyanate by \cite{Rodriguez-Almeida21}
toward G+0.693-0.027, a shocked region located close to Sgr B2(N)
(CH$_3$NCO/\textit{trans}-C$_2$H$_3$NCO > 26). For the \textit{cis} conformer, considered as an independent
species, they obtained a lower limit of 7 for CH$_3$NCO/\textit{cis}-C$_2$H$_3$NCO but this cannot
be compared directly to the ratio we report in Table \ref{t:coldens} because, for the high
densities of Sgr B2(N1S), we assume an LTE distribution of both conformers,
and not independent species.
Because of its large vibrational partition function, the
upper limit we obtained for ethyl isocyanate toward Sgr B2(N1S) is less stringent than for vinyl isocyanate: we find that ethyl
isocyanate is at least 3 times less abundant than methyl isocyanate. For
comparison, propanal, C$_2$H$_5$CHO, and ethylamine, C$_2$H$_5$NH$_2$, were
both found to be at least 5 times less abundant than acetaldehyde, CH$_3$CHO,
and methylamine, CH$_3$NH$_2$, respectively, toward Sgr~B2(N1S) with the ReMoCA
survey \citep[][]{SanzNovo22,Margules22}. Therefore, it is likely that ethyl
isocyanate is at least twice less abundant than the upper limit derived above, which would be in line with the ratio
CH$_3$NCO/C$_2$H$_5$NCO of 8 found by \cite{Rodriguez-Almeida21} toward
G+0.693-0.027.
In contrast, the upper limit obtained for vinyl isocyanate toward Sgr~B2(N1S) is a bit more
stringent than the one derived toward the same source for vinylamine,
C$_2$H$_3$NH$_2$, that was found to be at least 8 times less abundant than
methylamine \citep[][]{Margules22}.

\section{Discussion}
\label{s:discussion}

\subsection{Laboratory spectroscopy of vinyl isocyanate}
\label{ss:lab}

Isocyanates are rather flexible molecules with plenty of anomalies in their rotational spectra \citep{Yamada1980,Koput1984,Cernicharo16,Pienkina2017,Kolesnikova18,Kolesnikova2019} and for vinyl isocyanate this has also proven to be the case. The ground state rotational spectrum of the \textit{trans} isomer suffered from strong perturbations which allowed only transitions involving levels up to $K_{a}=6$ to be analyzed without the loss of physical meaning of the fitted constants.
The origin of these perturbations can be understood once excited vibrational states are taken into consideration and the reduced energy level diagram (Fig. \ref{Ered}) is plotted.
Three excited vibrational states, namely $v_{18}=1$, $v_{13}=1$, and $v_{18}=2$, fall into the energy window of 200~cm$^{-1}$. Figure~\ref{spectrum} shows that our spectrum exhibits noticeable patterns assignable to these states on the basis of the spectroscopic constants from \cite{Kirby1978}, nevertheless, their low $K_{a}$ transitions were already heavily perturbed.
\cite{Kirby1978} estimated the frequencies of the associated vibrational modes $\nu_{18}$ and $\nu_{13}$ to 77(10)~cm$^{-1}$ and 200(20)~cm$^{-1}$, respectively, from microwave relative intensity measurements. We find a remarkable agreement between the literature value and the anharmonic frequency of 78~cm$^{-1}$ for the $\nu_{18}$ vibrational mode from our quantum-chemical calculations.
On the other hand, our computations indicated a significantly lower frequency for the $\nu_{13}$ mode (136~cm$^{-1}$) than previously reported.
This lower value leads to better agreement with our experimental spectrum; the rotational transitions in $v_{13}=1$ have on average slightly higher relative intensities than the same transitions in $v_{18}=2$ which is estimated to lie at 155~cm$^{-1}$.

The excited vibrational states $v_{18}=1$ and $v_{13}=1$ are in strong non-resonant Coriolis interaction, repelling each other, as evidenced by their $A$ rotational constants (54~601 and 70~532~MHz for $v_{18}=1$ and $v_{13}=1$, respectively, \citealt{Kirby1978}). The rotational energy levels in $v_{18}=1$ are thus pushed down. Since the ground state rotational constant $A$ is considerable ($\sim2$~cm$^{-1}$ or 62~586~MHz) in comparison with the energy of $v_{18}=1$, the rotational levels in the ground state quickly reach in energy the levels in $v_{18}=1$ and rovibrational interactions might appear already for $K_{a}=7$ of the ground state (see Fig.~\ref{Ered}). Resonant interactions between $v_{18}=1$ and $v_{13}=1$ (e.g., between $K_{a}=8$ and 5, $K_{a}=9$ and 6, etc.) will further complicate the situation.
Figure~\ref{Ered} also shows that the $v_{13}=1$ state lies close in energy to $v_{18}=2$ and their rotational energy levels cross at $K_{a}=5$ and 6. Effects of this Fermi interaction
might be non-negligible as shown, for example, in \textit{n}-propyl cyanide \citep{Liu2019}.

All in all, the ground vibrational state cannot be completely analyzed without $v_{18}=1$ which cannot be treated without $v_{13}=1$ which in turn cannot be analyzed without $v_{18}=2$. Similar interactions among multiple vibrational states were observed in the rotational spectra of quasi-linear molecules such as HNCO \citep{Yamada1980} and hydrazoic acid (HN$_3$, \citealt{Hegelund1987,Vavra2017}) and other near-prolate species such as vinyl cyanide (C$_2$H$_3$CN, \citealt{Kisiel2009,Kisiel2012}) and \textit{n}-propyl cyanide (\textit{n}-C$_3$H$_7$CN, \citealt{Liu2019}).
The above network of interacting states is already very complicated and is expected to be even more complex due to possible coupling with other excited vibrational states which are not included in Fig.~\ref{Ered} for simplicity. In particular, $v_{18}=3$, ($v_{18}=1$, $v_{13}=1$), and $v_{13}=2$ might be at play and would make the analysis extremely challenging. A logical step toward the understanding of these interactions would be the measurement and analysis
of a high-resolution vibrational spectrum of vinyl isocyanate. For the time being, we prefer to make our laboratory data available for astrophysical applications even though our data set is limited in terms of $K_{a}$ in comparison with "well-behaved" molecular systems.
We emphasize that given the large value of the $A$ rotational constant, $K_{a}=6$ is more than enough to identify the molecule in fairly warm environments such as hot cores.
Of course, our results are also perfectly suitable for a search of the molecule in colder interstellar sources.
For CH$_3$NCO, only $K_{a}\leq 3$ transitions were experimentally accessible at the time of its search in space and led to its detection \citep{Halfen15,Cernicharo16}.

      \begin{figure}[ht]
   \centering
   \includegraphics[trim = 0mm 5mm 0mm 0mm, clip, width=8.9cm]{Graph1.eps}
      \caption{Diagram of reduced energies for the ground state (black), $v_{18}=1$ (red), $v_{13}=1$ (blue), and $v_{18}=2$ (green) excited vibrational states in \textit{trans} vinyl isocyanate. The reduced energies $E_{\text{red}}$ are calculated as $E_{\text{red}}=E - (B+C)J(J+1)/2$ where $E$ corresponds to the energy of rotational levels. Their values are obtained from the experimental spectroscopic constants and calculated vibrational energies.
      }
      \label{Ered}
   \end{figure}

The set of the spectroscopic constants for \textit{trans} vinyl isocyanate obtained in this work is definitely more complete and accurate in comparison with the original work of \cite{Kirby1978}.
Table~\ref{constants} illustrates that the previous values for the rotational and quartic centrifugal distortion constants are improved by up to two orders of magnitude. Furthermore, the physical meaning of those newly determined quantities is corroborated by the agreement between the fitted values and their quantum-chemical counterparts in Table~\ref{constants}.
Spectral predictions for $K_{a} < 7$ generated using these constants thus serve as
an accurate observational reference, at least in the case when these are interpolations within the measured data sets. Although some transitions may reveal satisfactory predictive power outside the present data region, we do not recommend such extrapolations due to the amount and complexity of perturbations expected to appear at higher frequencies.

Final remarks concern the spectroscopic constants for \textit{cis} vinyl isocyanate.
We can infer from Table~\ref{constants} that their values are significantly better determined than previously; some of them by two orders of magnitude.
In addition, many centrifugal distortion constants are determined for the first time.
Table~\ref{constants} further illustrates that the \textit{cis} isomer analysis called for inclusion of centrifugal distortion terms up to 10$^{\text{th}}$ power in the angular momentum. The requirement for such a high expansion of the rotational Hamiltonian might be an indicative of rovibrational interactions with low-lying excited vibrational states. Here, the low-energy states $v_{18}=1$ and $v_{13}=1$ are predicted by our quantum-chemical calculations at 90 and 110 ~cm$^{-1}$, respectively. Since the rotational constant $A$ is three times smaller than that of the \textit{trans} isomer, such interaction would affect the rotational energy levels with higher $K_{a}$. To assess whether the interaction results in contributions to the centrifugal distortion constants, one can compare their experimental and quantum-chemical values.
Table \ref{constants} shows good correspondence between our quartic and sextic constants and those calculated at CCSD/cc-pVTZ level of theory except for $\phi_{JK}$ which is opposite in sign.
Thus, if there existed an interaction with excited vibrational states it would probably become noticeable at the sextic and higher-order level of the Hamiltonian. Unfortunately, we did not find the rotational transitions in excited vibrational states in our spectra that could address this issue.

\subsection{The chemistry of methyl, vinyl, and ethyl isocyanate}
\label{s:chemistry}

\subsubsection{Methyl isocyanate}

While methyl isocyanate is the only one of the three molecules listed in
Table~\ref{t:coldens} to have been definitively detected in our survey,
the chemistry by which it forms is still uncertain.
\citet{Halfen15} proposed gas-phase reactions between the methyl radical,
CH$_3$, and either HNCO (isocyanic acid) or HOCN (cyanic acid) as plausible
mechanisms:
\begin{equation}
{\rm CH}_3 + {\rm HNCO} \rightarrow {\rm CH}_3{\rm NCO} + {\rm H} \label{reac1}
\end{equation}
\begin{equation}
{\rm CH}_3 + {\rm HOCN} \rightarrow {\rm CH}_3{\rm NCO} + {\rm H} \label{reac2}
\end{equation}
While HNCO is substantially more abundant than HOCN in the ISM
\citep[][]{Bruenken10}, it is also the more stable structure; as noted by
\citet{Halfen15}, reaction \ref{reac1} should be endothermic. However, a
precise determination of this is challenging, as the enthalpy of formation of
methyl isocyanate is poorly defined in the literature. The CRC Handbook of
Chemistry and Physics \citep[][]{Haynes17} provides only a value for the
liquid phase ($\Delta_{f}H^{0}(l)=-92.0$~kJ~mol$^{-1}$) rather than the gas
phase. But even crudely adjusting this value to take account of the enthalpy
of vaporization, it appears almost certain that reaction \ref{reac1} would be
highly endothermic (by more than 100~kJ~mol$^{-1}$).
Calculations by \citet{Majumdar2017} indeed indicate the reaction to be endothermic by
77~kJ~mol$^{-1}$, with a transition state that lies 83~kJ~mol$^{-1}$ above the entrance level.
Furthermore, it is likely
that even reaction \ref{reac2} is somewhat endothermic. Substantial activation
energy barriers might also be expected for both reactions, suggesting that
either route would be quite inefficient in the ISM.

\citet{Halfen15} also proposed ion-molecule reactions between HNCO/HOCN and
CH$_5^+$ to produce protonated methyl isocyanate; however, such processes
involving CH$_5^+$ typically result in proton transfer in laboratory
experiments, indicating that protonated HNCO/HOCN would be the preferred
products. It therefore remains unclear whether there is a plausible gas-phase
mechanism that could produce CH$_3$NCO in sufficient quantities to explain
observations. As noted by \citet{Cernicharo16}, the detection of CH$_3$NCO
only in high-temperature regions may indicate that methyl isocyanate
originates on dust-grain surfaces.

Chemical models have been used to study the formation of CH$_3$NCO and related
species on interstellar dust grains. \citet{Belloche17} considered a direct
radical-radical association reaction:
\begin{equation}
{\rm CH}_3 + {\rm OCN} \rightarrow {\rm CH}_3{\rm NCO} \label{reac3}
\end{equation}
The radicals would be produced by the photodissociation of, or
chemical H-abstraction from, CH$_4$ and HNCO in the dust-grain ice mantles,
while CH$_3$ could also be produced by repetitive H addition to atomic carbon
on the grain/ice surfaces. Experiments presented by \citet{Ligterink17} indeed
show that CH$_3$NCO may be formed by UV irradiation of mixed CH$_4$:HNCO ices.
The precise mechanism of production was not determined, but was assumed to be
either reaction \ref{reac3} or reaction \ref{reac1}, which would be
endothermic also in the solid phase. As with reaction \ref{reac1}, the
alternative branch CH$_3$ + HNCO $\rightarrow$ CH$_4$ + OCN is endothermic.
However, the production of excited CH$_3$ as a photoproduct of CH$_4$ might be
sufficient to remove these difficulties in both cases.
\citeauthor{Ligterink17} also proposed that the OCN$^-$ ion, which was
produced abundantly in the experiments, could be active in forming CH$_3$NCO.
In their observational study, \citet{Ligterink2021} concluded that reaction \ref{reac3}, occurring during the dark cloud stage of evolution, would be a plausible explanation for the uniform CH$_3$NCO/HNCO ratio of around 10\% observed toward various sources.

The astrochemical model of \citet{Belloche17} indicated that, given an
appropriate degree of grain-surface formation of HNCO, methyl isocyanate could
also be formed on the grains during the warm-up phase of a hot core, via
reaction \ref{reac3}. The radicals would become mobile, and thus reactive, at
elevated temperatures; the model results provided an acceptable match to the
observed abundances.

However, the more recent models of \citet{Garrod22} have challenged the purely
diffusive picture of hot-core grain-surface chemistry, by including so-called
non-diffusive reactions on the grain surfaces and within the bulk ices
\citep[][]{Jin20}. Furthermore, these models restrict the mobility of most
chemical species in the bulk, allowing only H and H$_2$ to diffuse internally.
Larger species may diffuse only on the grain/ice surfaces themselves. The
non-diffusive reaction mechanisms in the model nevertheless allow
radical-radical reactions in the bulk ice to occur, but with rates driven by
the processes that initiate the radical production that precedes them. In this
scenario, the efficiency of bulk-ice chemistry is only weakly determined by
the ice temperature, while radical reactions in the bulk can occur in
principle at any temperature if, for example, photodissociation of a stable
molecule in the bulk ice occurs in the presence of a radical with which one of
the photoproducts may rapidly react.

Unfortunately, in these new models, CH$_3$NCO is severely underproduced on the
grains; OCN radicals tend to recombine quickly with mobile H atoms, both on
the surface and in the bulk ice, providing little opportunity for reaction
with CH$_3$. Furthermore, the endothermicity of the H-abstraction reaction
H + HNCO $\rightarrow$ OCN + H$_2$ removes an alternative means of reforming
OCN and thus raising its abundance on the grains. Meanwhile, a competing
process, H + HNCO $\rightarrow$ NH$_2$CO, is exothermic with only a modest
barrier \citep[1390 K;][]{Nguyen96}. The removal of the bulk diffusion
mechanisms for OCN and CH$_3$ also inhibits the diffusive reactions that
produced CH$_3$NCO effectively at higher temperatures in the older models.
HNCO, however, is itself formed effectively on the grain surfaces at very low
temperatures in these models \citep[see][]{Garrod22}, through the
barrier-mediated reaction NH + CO $\rightarrow$ HNCO.

Thus, while photodissociation of CH$_4$ and HNCO, followed by radical addition,
still appears to be the main production mechanism for methyl isocyanate in the
newest astrochemical models, the resulting abundances are several orders of
magnitude lower than the observed values.

Several other gas-grain modeling studies have been conducted to explain observed gas-phase CH$_3$NCO abundances toward cold sources and warm star-forming regions \citep{Martin-Domenech2017,Quenard2018}. Those models adopted the gas-phase and grain-surface reaction mechanisms noted above; they concluded that reactions \ref{reac1} and \ref{reac2} are dominant contributors to CH$_3$NCO production following ice mantle desorption, based on the reactions occurring at the collisional rate, i.e. somewhere on the order of 10$^{-10}$ cm$^{3}$~s$^{-1}$. However, as noted above, the substantial endothermicities of those reactions would likely render them highly inefficient; some alternative formation mechanism would therefore still be required, whether in the gas phase or on the grains.

Noting the problems with the suggested gas-phase reactions, \citet{Majumdar2017} proposed two new mechanisms for grain-surface CH$_3$NCO production. The first involves the reaction of an H atom with an HCN molecule while the latter is in a van der Waals complex with a CO molecule; i.e.
\begin{equation}
{\rm H} + {\rm HCN}...{\rm CO} \rightarrow {\rm H}_2{\rm CN}...{\rm CO} \rightarrow {\rm CH}_2{\rm NCO} \label{reac_maj1}
\end{equation}
The energy produced in the initial reaction would allow the activation energy barrier to be overcome for an immediate follow-on reaction, producing CH$_2$NCO; the latter radical could then be rapidly hydrogenated by H to form methyl isocyanate. These authors' other mechanism involves a barrieless reaction between atomic N and the radical CH$_3$CO, for which they calculate that the production of CH$_3$NCO is the most energetically favorable outcome:
\begin{equation}
{\rm N} + {\rm CH}_3{\rm CO} \rightarrow {\rm CH}_3{\rm NCO} \label{reac_maj2}
\end{equation}

\citet{Majumdar2017} find that reactions \ref{reac_maj1} and \ref{reac_maj2} contribute to the production CH$_3$NCO sufficiently to explain observational values. However, the efficiency of reaction \ref{reac_maj1} is not well defined and is dependent on the precise reaction dynamics involved, as well as on the choice of barrier to the initial reaction. Reaction \ref{reac_maj2} relies on the hydrogenation of ketene (CH$_2$CO) to form the necessary radical, which is also a barrier-dependent process. The results are encouraging, although further testing of these mechanisms is likely required to determine their true effectiveness.

One further mechanism might be plausible for grain-surface production of
CH$_3$NCO. \citet{Garrod22} introduced a number of new reactions into their
chemical network involving methylene, CH$_2$. In its ground (triplet) state,
methylene is a diradical; \citeauthor{Garrod22} proposed that H-abstraction
reactions involving CH$_2$ and stable molecules on grain surfaces would lead
to production of two radicals that could immediately react with each other
to form a single product. It is unclear whether the initial abstraction
reaction between CH$_2$ and HNCO would be exothermic, but it would
almost certainly have an activation energy barrier.
However, a direct addition reaction,
\begin{equation}
{\rm CH}_2 + {\rm HNCO} \rightarrow {\rm CH}_3{\rm NCO} \label{reac4}
\end{equation}
would be strongly exothermic ($\sim$300~kJ~mol$^{-1}$). The attack
of the methylene radical on the C=N double bond in HNCO would likely have an
activation energy barrier, although the large exothermicity of the reaction
might suggest a relatively small barrier compared with, for example, the
above-mentioned addition reaction H + HNCO $\rightarrow$ NH$_2$CO (exothermic
by around 140~kJ~mol$^{-1}$). However, as the methylene reaction does not
explicitly involve an H atom, there may be no quantum tunneling mechanism
available to overcome the barrier, unlike in the case of many grain-surface
reactions involving atomic H. The determination of the efficiency of reaction
\ref{reac4} would require detailed calculations. But if CH$_2$ is a common
photodissociation product of CH$_4$, as is often assumed in the chemical
networks, then the spontaneous production of methylene in proximity to HNCO in
the bulk ice could plausibly produce methyl isocyanate in appreciable
quantities. Likewise, if the abstraction process is exothermic, then H-atom
tunneling between HNCO and CH$_2$ might allow it to proceed effectively,
producing CH$_3$NCO in a two-step process. As well as the bulk ice process,
formation of CH$_2$ on the grain/ice surface, from atomic carbon, might also
lead to reaction with HNCO.
Such a mechanism would presumably retain the observationally determined
correlation between HNCO and CH$_3$NCO \citep{Ligterink2021,Colzi2021}, once both molecules were desorbed into the gas phase at elevated temperatures.

Alternatively, as mentioned above, if CH$_3$ is formed in an excited state
through CH$_4$ photodissociation in the bulk ice, direct reaction
 of the methyl radical
with abundant
HNCO might proceed efficiently.

\subsubsection{Vinyl and ethyl isocyanate}

In spite of the nondetection of vinyl and ethyl isocyanate toward Sgr B2(N1S), it is valuable to
consider their possible production mechanisms. Although we do not currently
have chemical models that include either species, we may speculate on possible
outcomes based on molecules that are presently included.

The lack of a gas-phase formation mechanism for CH$_3$NCO would also suggest
that chemistry on grains or within the ice mantles is the most plausible
scenario for the larger molecules. We may again propose radical addition
reactions involving OCN, i.e.
\begin{equation}
{\rm C}_2{\rm H}_3 + {\rm OCN} \rightarrow {\rm C}_2{\rm H}_3{\rm NCO} \label{reac5}
\end{equation}
\begin{equation}
{\rm C}_2{\rm H}_5 + {\rm OCN} \rightarrow {\rm C}_2{\rm H}_5{\rm NCO} \label{reac6}
\end{equation}
Reaction \ref{reac6} was first suggested by \citet{Rodriguez-Almeida21}.
Assuming that reaction \ref{reac3} is the most important process for
CH$_3$NCO production, the relative abundances of the radicals CH$_3$,
C$_2$H$_3$, and C$_2$H$_5$ in the ice might indicate the expected ratio of the
isocyanates (on the expectation that the photodissociation of HNCO would
provide the driving rate for all three reactions, \ref{reac3}, \ref{reac5},
and \ref{reac6}). However, in the new \citet{Garrod22} models, the ratios of
the peak abundances (during the cold collapse stage) are approximately
CH$_3$:C$_2$H$_3$:C$_2$H$_5$ = 30:1:65. While this appears consistent
with the observed ratio of the column density of methyl isocyanate to the
upper limit for vinyl isocyanate, it would also indicate that the abundance of
ethyl isocyanate should exceed that of methyl isocyanate. As noted in
Sect.~\ref{ss:nondetection_remoca}, such a large ratio is not expected.

However, reaction \ref{reac3} does not produce adequate quantities of CH$_3$NCO
in the models. If an alternative process is active at least for the production
of this molecule, while reactions \ref{reac5} and \ref{reac6} were to remain
the principal routes to vinyl and ethyl cyanide, then this would indicate that
the real column densities of the latter species should be far less than the
observational upper limits.

If the methylene reaction proposed above -- reaction \ref{reac4} -- should in
fact be the dominant production route for CH$_3$NCO, then the absence of
analogous mechanisms that form vinyl and ethyl cyanide is readily understood;
there are no equivalent chemical species that would produce C$_2$H$_3$NCO or
C$_2$H$_5$NCO by a similar reaction with HNCO. In this case, the most likely
production mechanism for ethyl isocyanate could be the photodissociaton
of, or H-abstraction from, methyl isocyanate itself, followed by the addition of
a methyl group, e.g.:
\begin{equation}
{\rm CH}_3{\rm NCO} + h\nu \rightarrow {\rm CH}_2{\rm NCO} + {\rm H}
\end{equation}
\begin{equation}
{\rm CH}_3 + {\rm CH}_2{\rm NCO} \rightarrow {\rm C}_2{\rm H}_5{\rm NCO}
\end{equation}
The H-abstraction initiated process might include the two-step insertion of
methylene into a C-H bond in methyl isocyanate. The astrochemical models
indicate that in cases in which H-abstraction/photodissociation and methyl
addition is the main formation mechanism, such as with ethylamine production
from methylamine,
the smaller homologue achieves an abundance around 10 times greater than that of the larger homologue.
Such would be in line with our observational ratio of
methyl to ethyl
isocyanate. Furthermore, \citet{Rodriguez-Almeida21} recently detected
ethyl isocyanate toward the Galactic Center cloud G+0.693-0.027, finding a
ratio CH$_3$NCO:C$_2$H$_5$NCO = $8 \pm 1$, which is also in good agreement
with the typical modeling outcome.

Once again, there is unlikely to be a comparable mechanism leading to
formation of a vinyl group, which would also tend to make the abundance of
vinyl isocyanate inferior to those of the other two.

The above ideas are, of course, highly speculative. A full chemical model
including all of these species would be desirable, although there remain a
number of poorly-defined quantities that could be important -- not least, the
possible efficiency of reaction \ref{reac4}, and the precise mechanisms
involved in experimental UV-induced production of methyl isocyanate.

\section{Conclusions}
\textbf{\label{s:conclusions}}

Laboratory rotational spectroscopy of vinyl isocyanate has been undertaken in the frequency regions 127.5--218 and 285--330~GHz. Over 1000 transition lines were assigned and measured
for the ground vibrational states of its \textit{trans} and \textit{cis} isomers. The present work provides significantly more precise values of the spectroscopic parameters which agree with those from accompanying high-level quantum-chemical computations. We report a nondetection of both vinyl and ethyl isocyanate toward
the main hot core of Sgr~B2(N) that was targeted with ALMA. We find that these
molecules are at least 11 and 3 times less abundant than methyl isocyanate,
respectively.
Despite the nondetection of vinyl isocyanate in Sgr~B2(N) the present work represents a substantial improvement on previous microwave studies below 40 GHz and meets the requirements
for further searches of this species in the interstellar space.
To this end, spectral predictions are provided in Tables~\ref{predictions-trans} and \ref{predictions-cis} and will be also available in CDMS.

\begin{acknowledgements}

The spectroscopic part of this work has been funded by the Czech Science Foundation (GACR, grant No. 19-25116Y). L.K., K.V., J.K., and K.L. gratefully acknowledge this financial support.
L.K., J.K., K.L., and P.K. thank the financial support from the Ministry of Education, Youth and Sports of the Czech Republic (MSMT) within the Mobility grant No. 8J21FR006.
Computational resources were supplied by the project "e-Infrastruktura CZ" (e-INFRA CZ LM2018140) supported by the Ministry of Education, Youth and Sports of the Czech Republic. Computational resources were provided by the ELIXIR-CZ project (LM2018131), part of the international ELIXIR infrastructure.
R.T.G. thanks E. Herbst for helpful discussions.
This paper makes use of the following ALMA data:
ADS/JAO.ALMA\#2016.1.00074.S.
ALMA is a partnership of ESO (representing its member states), NSF (USA), and
NINS (Japan), together with NRC (Canada), NSC and ASIAA (Taiwan), and KASI
(Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA
Observatory is operated by ESO, AUI/NRAO, and NAOJ. The interferometric data
are available in the ALMA archive at https://almascience.eso.org/aq/.
Part of this work has been carried out within the Collaborative
Research Centre 956, sub-project B3, funded by the Deutsche
Forschungsgemeinschaft (DFG) -- project ID 184018867.
R.T.G. acknowledges funding from the Astronomy \& Astrophysics program
of the National Science Foundation (grant No. AST 19-06489).
J.-C.G. thanks the Barrande project No. 46662VH, the Centre National d'Etudes Spatiales (CNES) and the "Programme National Physique et Chimie du Milieu Interstellaire" (PCMI) of CNRS/INSU with INC/INP co-funded by CEA and CNES for a grant.

\end{acknowledgements}

redpajama_set_name: RedPajamaArXiv


Aged Habano cigars taste different to the equivalent recent production. It is an acquired taste and not for beginners. There are auctions for thousands of dollars for cigars which date pre-embargo. There are very high prices paid for each decade after that. The cigars we are offering have matured a few years. The oldest are from 1998 and the youngest are from 2003.
These cigars have matured in Cuba and have just been inspected for quality by Habanos and then in our humidor by us. A few of our VIP clients have had some and have already bought them in batches. We will soon run out of these and have no idea if and when we will get more. Although based on the comments by our customers, and especially by our long time customers, we will ask for more.
Why smoke a matured cigar? This is what our supplier says, " During the early years the cigar is left to mature the general flavor remains but as the nicotine and ammonia disappear the cigar "mellows" and the flavor is less harsh" .
As we said these cigars are for connoisseurs, and to them this is a treat. Enjoy.
Note: Although the system states otherwise the codes are guaranteed for these boxes.


A UK law has quietly passed through Parliament which allows for radioactive waste dumps to bypass the planning system, local authorities or public opinion. The new legislation is opposed by anti-nuclear activists.
Under the new law, Britain's radioactive waste from medical use, weapons and power stations which has been stockpiled for 50 years may be dumped, circumventing local requirements.
Sites will be chosen by the secretary of state for energy and climate change. As of last week they are considered "nationally significant infrastructure projects." While the planning inspectorate could recommend sites for the nuclear waste piles, the secretary does not necessarily need to follow the advice. Local communities and councils can dispute the details, but can't stop the process.
The law was passed in the Parliament's last working hours before it was prorogued for the general election and was noticed only by anti-nuclear activists and local opponents.
"Communities will be rightly concerned about any attempts to foist a radioactive waste dump on them. We urgently need a long-term management plan for the radioactive waste we've already created, but decisions mustn't be taken away from local people who have to live with the impacts," Naomi Luhde-Thompson, planning advisor for Friends of the Earth told the Guardian.
Opponents' concern is that the move means lawmakers are desperate to resolve a long-lasting nuclear waste problem as they doubt that the plan to create a new generation of nuclear power stations could get public support.
Zac Goldsmith, one of the few MPs who voted against the law, said such a big change should be done with more public debate.
"It strips local authorities of the ability to stop waste being dumped in their communities. If there had been a debate, there could have been a different outcome: most of the MPs who voted probably didn't know what they were voting for," he said.
Meanwhile even when a site is chosen, it will take another 27 years to build a dump and will cost from £4 to 5.6 billion, according to shadow energy minister, Julie Elliott.
At least four attempts to find the right place for permanent storage facility have been made since 1976. All were postponed after strong protests.
During the last 50 years, Britain has collected 4.5 million cubic meters of radioactive waste, according to the Guardian. They are kept in safe containers around the country and cost £3 billion annually, with two thirds of the sum coming from taxpayers.
According to Department for Energy and Climate Change's white paper published in 2014, ministers should better to work with public support, but if "at some point in the future such an approach does not look likely to work," there is a right to take more aggressive action on planning.
Germany has shelved plans to bury high-level radioactive waste, while Japan and France are reassessing their approaches.
The only existing high-level radioactive underground waste stockpile in the US' New Mexico was closed last year following two accidents.


text:
Photo added by Brigitte1999
Charles J. Grandy
Vermont, USA
31 Dec 1899 (aged 80)
Wells, Faribault County, Minnesota, USA
Wells, Faribault County, Minnesota, USA Show Map
Name: Charles J. Grandy
Company: C
Veteran; promoted Corporal, Sergeant.
Place: Vermont
Mustered In
Rank: Private
Residence prior to military service: Vermont; New York (about 1829-1854); Wisconsin (1854-1857); Carlston Township, Freeborn County, Minnesota
Vocation prior to military service: Farmer
Date: Unknown (betwee 1883 and 1900)
Place: Unknown
Burial: Unknown
Mustered Out
Rank: Sergeant
Residence following military service: Carlston Township, Freeborn County, Minnesota
Vocation following military service: Farmer
Charles J. Grandy Biography and Civil War Narrative
Charles J. Grandy was born July 20, 1819, in Vermont, possibly the son of Charles S. and Polly (Thompson) Grandy. Around the age of 10, Charles and his family moved to New York. In 1846 married Miss Huldah Winters, born April 1824 in New York. Living in New York, Charles and Huldah had at least three children: daughter Elizabeth Ann (born May 1846), daughter Emma E. (born about 1849), and son Henry (born about 1851). In 1854 the Charles Grandy family moved to a farm in Wisconsin. Son Samuel was born about 1856. In 1857 the family moved once again, this time to Carlston Township, Freeborn County, Minnesota. Son Francis was born about 1858 and son George W. was born October 1860.
On February 18, 1862, 42-year-old Charles Grandy enlisted in Company C of the 5th Minnesota Volunteer Infantry Regiment. Company C began its active service with garrison duty at Fort Ripley, north of Little Falls, Minnesota. On June 19, Private C. J. Grandy left Fort Ripley with a detachment of 50 men under the command of Lieutenant Timothy Sheehan to report to Fort Ridgely near the Minnesota River. Marching about 200 miles via Elk River and Henderson, they reached Fort Ridgely on the evening of June 28th, and reported to Captain Marsh who commanded the post. On June 29th, the detachment was sent on to the Sioux Agency on the Yellow Medicine River to help preserve order during the annuity payment to the Sioux. They camped at the Lower Sioux Agency along the Minnesota River the night of June 30th, and arrived at the Upper Sioux Agency at Yellow Medicine on July 2nd, reporting to Major Thomas Galbraith, the Sioux agent at that place.
On August 4th, about 800 Sioux warriors surrounded the camp of the detachment and stormed a government supply warehouse, which the soldiers defended. After annuity goods were distributed to the Indians, the detachment marched back to Fort Ridgely, arriving on the evening of August 12th. Five days later (August 17th), Private Grandy and Lieutenant Sheehan's detachment began marching back to Fort Ripley to join the rest of their company who had remained there.
News that a massacre was taking place at the Lower Sioux Agency arrived at Fort Ridgely the next morning (Monday, August 18th) so Captain Marsh quickly sent a dispatch to the Company C detachment calling them back to Fort Ridgely.
Marsh left Fort Ridgely leading a rescue team to the Lower Sioux Agency and left Lieutenant Thomas P. Gere in command at the fort. When the orders reached Grandy's Company C on Monday evening, they had already marched 42 miles from Fort Ridgely and were setting up camp between New Auburn and Glencoe. Sheehan immediately led a forced march back to Fort Ridgely and arrived back at the fort on Tuesday. They had marched 42 miles in 9 1/2 hours. Upon their arrival at Fort Ridgely, Lieutenant Sheehan took command of the fort. Meanwhile, about 2 miles west of the fort, Indians under the leadership of Little Crow were congregated and planning their movements.
On Wednesday, August 20th, while Little Crow approached the fort from the west, a party of 500-600 Indians attacked from the northeast. Soon the fort was surrounded, and the Indians kept up their attack on the fort for five hours, the defenders responding with artillery and muskets. At nightfall the firing ceased and Little Crow withdrew his forces to the lower agency.
Two days later on Friday, August 22nd, Little Crow again attacked Fort Ridgely, this time with a force of 1200-1500 men. For six hours the battle continued, but once again the fort was successfully defended. In the following days, defensive works were strengthened. On Wednesday, August 27th, additional reinforcements arrived. On the monument at Fort Ridgely, "C. J. Grandy" is inscribed as one of the privates of Company C who defended the fort.
Charles Grandy and the Company C detachment once again left Fort Ridgely on September 18th to return to their companions at Fort Ripley. When they had concluded their service at Fort Ripley, Company C joined the rest of the 5th Minnesota on December 12, 1862, near Oxford, Mississippi. From mid-May to early July 1863, the 5th Minnesota participated in the Siege of Vicksburg, Mississippi, serving in Mower's 2nd Brigade in the 3rd Division (Tuttle) of the 15th Army Corps (Sherman), Army of the Tennessee (Grant). On May 22nd they participated in a large assault on Vicksburg. While the siege was going on they went on expeditions to Sartaria and Mechanicsburg, Mississippi, and to Richmond, Louisiana. They also toiled in a failed attempt to divert the Mississippi River through a canal. The Confederates surrendered Vicksburg to the Union Army on July 4, 1863.
In early 1864, Grandy and many of the rest of the soldiers of the 5th Minnesota re-enlisted as veterans. That spring they particated in the less-than-successful Red River Campaign that took them through much of Louisiana between March 10 and May 22, 1864. On December 15-16, 1864 at the Battle of Nashville, the 5th Minnesota participated in a route of General Hood's Confederate Army, and from March 7 to April 12, 1865, they were involved in the Campaign against Mobile, Alabama and its Defenses. During the course of the war, Private Grandy was promoted first to Corporal and then to Sergeant. He was mustered out with the regiment on September 6, 1865.
Following the Civil War, Charles J. Grandy returned to his home in Carlston Township, Freeborn County, Minnesota, where he returned to farming. The 1870 U.S. Census shows Charles and Huldah Grandy farming in Carlston Township, with four children: son Henry S. (age 19; works on farm), son Francis M. (age 12; works on farm), son George W. (age 9), and daughter "Madora A." (age 2).
In 1880 Charles continued to farm in Carlston Township. Children who remained in the household were George (age 19) and Medora (age 12). Also living with them were Charles' sister Lydia Winstanley (sp?), a 47-year-old Milliner (hat maker) born in New York. In 1883 a list of military pensioners was compiled. Charles J. Grandy was included in the Freeborn county list. His "cause for which pensioned" was listed as "chr. diarrhea & dis. of rectum." His monthly rate was $8.00 with his pension having started in December 1879.
Charles J. Grandy apparently died between 1883 and 1900; the 1900 U. S. census shows his wife Huldah (age 76) living with their daughter, Elizabeth (age 54) and her husband, George Hawkins (age 64; born in England in June 1835). Their home was located in Minnesota Lake Township, Faribault County, Minnesota, about 15 miles northwest of the Grandy home in Carlston Township. Meanwhile, Huldah's son George was a 40-year-old Farm Laborer who boarded with O.D. Ackerman in Foster Township, Faribault County. Huldah continued to live with Elizabeth and George in 1910, and George (Grandy) had also moved in. Huldah's son-in-law, George Hawkins, died March 18, 1912, in Faribault County, Minnesota, and Huldah Grandy died four and a half years later on November 20, 1916, also in Faribault County.
With permission:
http://home.comcast.net/~timbode07/5thMinnesota/Grandy_Charles.html
Thank you Tim Bode.
Huldah Winters Grandy
1824–1916 (m. 1846)
Elisabeth Ann Grandy Hawkins
George W. Grandy
See more Grandy memorials in:
Faribault County
Created by: Susan M. Bonn
Added: 3 Aug 2012
Find a Grave, database and images (https://www.findagrave.com/memorial/94773083/charles-j-grandy : accessed ), memorial page for Charles J. Grandy (24 Jul 1819–31 Dec 1899), Find a Grave Memorial ID 94773083, citing Rosehill Cemetery, Wells, Faribault County, Minnesota, USA ; Maintained by Susan M. Bonn (contributor 47697675) .
Add Photos for Charles J. Grandy
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redpajama_set_name: RedPajamaCommonCrawl


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Flight Centre UK has been recognised as one of this year's Best Workplaces in the UK, for the fourth year running. This accolade sees the company appearing at number 19, as revealed at the Great Place to Work® Awards Ceremony held at The Brewery, London.
Flight Centre UK is committed to ensuring its employees are happy through a range of benefits that promote a positive, productive and supportive workplace culture. Award nights, performance-related pay, travel discounts, in-house financial advisors and a flat structure where employees have access to leaders at any time, are just some of the benefits the company offers its employees.
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You need to be a member of San Augustine, TX to add comments!
Only reason I asked is because I was getting quite a few responses in red text when I entered them into the queries in the RRC site.
Is it safe to assume that the API numbers for all wells in San Augustine Start with 42-405?
Just got notice of May 29,2018 payment.
Our our royalty interest was cut in half ?
I started a new discussion about Aethon extended laterals & production sharing agreements by pasting your comment. I hope you don't mind.
Yeah, what's goin on here? I guess with the price where it is there's nothing to talk about. I was told late last year that XTO was gonna drill on the past my property was in. I can't find a link to the railroad commission site to look up the name of the well that I was given.
San Augustine is Dead Silent.


An American Avocet, resplendent in its breeding finery, chatters loudly as it flies over the marsh.
It doesn't take long to find the reason for the reason behind the adult chasing down every Crow and Turkey Vulture in the area.
Two chicks old enough to browse the shallows and feed on their own. They run back to the female to warm up under her wings when the late afternoon chill sets in.
Overhead threats safely averted, the male takes a break.
A Great Egret on its way out into the farthest reaches of the marsh.
Meanwhile, Ground Squirrels gather what I assume is nesting material, and scamper underground with their bounty.
and then scratches an itch.
A Barn Swallow rests for a moment as the sun begins to set on the marsh.


text:
MPs reflect on twenty years of devolution
By Chris Young on 19 July 2019
MPs debated the first two decades of devolution in a Commons debate led by the Scottish and Welsh Affairs committees last week.
Although this was a wide-ranging debate covering the recent report and recommendations of the Scottish Affairs Committee's Inquiry into the relationship between the UK and Scottish Government, there was time to talk tax.
Leading the debate, SNP MP Pete Wishart noted that the devolution of tax setting powers had been an important milestone in the coming of age of the Scottish Parliament.
Scottish Conservative MP David Duguid expressed frustration at the approach taken by the Scottish Government to taxation, repeating his party's message about Scotland being "the highest taxed part of the UK".
Ayrshire MP Patricia Gibson (SNP), lamented the Scottish Parliament's lack of control over tax but said that the "day will come" when Holyrood has control over all aspects of taxation and spending. Tommy Sheppard MP, in a later contribution, suggested that control over levers of corporate taxation could strengthen Holyrood's fiscal levers.
David Linden (SNP) lamented the criticism focused on the Scottish Government when it sought to use its tax powers to improve society, referencing the moniker "Nat tax" used by opposition politicians in Scotland to attack the government.
In contrast, the Labour MP Hugh Gaffney suggested that the Scottish Parliament could make better use of its powers to deliver "real change" for the people of Scotland.
Mr Gaffney repeated Scottish Labour's support for the introduction of a new 50 pence top tax rate as a means of supporting investment in public services.
Plaid Cymru MP Hywel Williams said that tax devolution for Wales had shifted perceptions of the Welsh Assembly from being a "glorified county council" to "law making body".
Welsh Labour MP Susan Elan Jones, suggested that the evolution of Welsh devolution needed to be accompanied by consideration of the needs of the nations and regions of the UK, many of whom are seeking greater control over their own fiscal affairs.
The debate took place a week before the publication by the Institute for Government of a new report evaluating twenty years of devolution.
The report suggests that the devolution have enabled the "separate identities" of Scotland, Wales and Northern Ireland to contribute to varying degrees of constitutional change.
In Scotland, this has led to a "legitimacy deficit" towards Westminster and its centralised authority, suggesting that voters in Scotland tend to trust their devolved bodies more than the UK Government.
The report also highlights the way devolution provides a fresh space for policy to be developed.
In the area of tax, early suggestions that Scotland would adopt "Scandinavian levels of taxation" have not come to fruition, replaced instead with a tax policy described in the paper as being neoliberal with a heart.
Nevertheless, the move to a new system of rates and bands of income tax and a reformed system of property taxation, while modest, has represented "a more decisive move than any of (Nicola Sturgeon's) predecessors had been prepared to make" and had prompted more "holistic" debate over the role of taxation in society.
Devolution in Wales had been more restricted than Scotland but has since grown to accommodate the partial transfer of tax powers to Cardiff.
But concerns remain that the benefits of devolution – dubbed the "devolution dividend" have yet to be felt in Wales and may be stymied by what the report suggests is the "one party (Labour) nature of Welsh politics".
Posted in: Welsh Taxes, Scottish Taxes


According to research your child can see skin color and hair textures as early as 6 months old. By two, your child is putting words to what he recognizes and between 4 to 6 years old, he is assimilating likenesses. Anything that is unfamiliar or unlike him is yucky or funny looking. 7 to 10 year olds are beginning to refine their understanding of how we are different and alike all at the same time.
I included these statistics to make the point that our children are aware of racial and ethnic differences. Our children do see color and that's a beautiful thing. Why have we made it so awkward to talk about how beautifully unique we are? We should embrace diversity by teaching our children about other cultures.
We should be the one "having the talk" about race, color, etc with our children. Not their peers or even their teachers!
I know you hear me say (figuratively through the pages) "Live out Loud", a lot, but that's how we teach our kids. I can tell them they are supposed to love people who are different from them, or I can show them by actually having people in our home who are culturally/ racially different than us. I choose to show them and show them often because they need to see that it is important to me and to us as a family.
When your child notices that people look physically different and begin to ask questions, don't panic. Kids can quickly pick up on your biases so give a simple, honest answer. God created us all. We may look different on the outside, but we are all the same on the inside.
I stated earlier that kids can pick up on your biases, so you have to live out loud first before you can tell them how to live. Examine your feelings about people of other ethnicities. Get to the root of any bias you may have and address it.
Children often learn to stereotype based on what they see or hear (this includes TV, whether it's cartoons, or the news). When you see or hear negative language about a people group, discuss with your children the inappropriateness of the comment. Also, when you don't know the answer to a question, say so. Let them know you grapple with the subject as well. Affirm that God is not a divisive God. He calls us to love others as we love ourselves.
It's funny that as multicultural as today's society is, most of us live in monochromatic or homogeneous neighborhoods, isolated from the experiences of cultural diversity. The options are endless of how to explore diversity: visit museums, read books, buy ethnically diverse toys, attend cultural events, learn about cultural celebrations, prepare ethnic dishes. A simple conversation about cultural diversity was always interesting in our home.
Kids who feel like they aren't valued tend to look for targets to release their own anger and frustration on- usually someone they deem less than or different from them. When we value and respect who our kids are as individuals, they develop self esteem that isn't easily swayed by what others say or think. Tell your child often how important he is. Tell him his value is determined by God, not by any person. Tell him God placed him here on earth with a purpose and a plan to carry that purpose out. YOUR job as parent is to help him discover that purpose.
God gave us the greatest commandment to love Him with all our heart, soul and mind. And the second greatest command was to love our neighbor as ourselves.
Our "neighbor" is anyone breathing on this planet, regardless of what they look or sound like. Let's raise our kids to love and be culturally aware of their "neighbors".


why small res and watermark?
it's unfortunate that we live in a world where people will take what they want. My self being a pretty idealistic person wouln't mind that, but also the possibility of someone taking it and using it for their own profit or other sleazy means. On top of that, I'm looking to be more proffesional, and this hopefully being my livelyhood I have to protect myself.
Blame all those out there who ruin it for everyone else, otherwise I would have no problem giving everything away.
any chance of requesting a higher resolution work (wallpaper) of yours?
Thats totally understandable for you to do that. Your work is consistently very good and it would be a shame for someone to take credit for something you have done.
why small res and watermark?it's unfortunate that we live in a world where people will take what they want. My self being a pretty idealistic person wouln't mind that, but also the possibility of someone taking it and using it for their own profit or other sleazy means. On top of that, I'm looking to be more proffesional, and this hopefully being my livelyhood I have to protect myself.


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Q: How to start a single timer and access it from multiple views? What is the recommended approach for starting a countdown NSTimer on one view and having it be accessible to stop interactively or to have run out in another?
I know one option is to have the NSTimer never turn off once kicked off and just use a global variable to determine whether to countdown or not but that seems inefficient.
More details of what I'm trying do:
In the main view I have a label that will update with the count down 00:00:00 and a button that I want to open a countdown UIDatePicker.
The second view with the UIDatePicker also has a start and stop button that will kick off or stop the countdown.
This view will close and the label on the original screen will display the countdown based on what the user selected previously.

A: It seems the timer you needed is independent from any of the views. You can use a singleton instance which will init once then be accessed anywhere. It's kind of like a global variable you mention above but if you have more than two views that need access to the timer singleton might be the most suitable choose

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SWARM! is an evening-length, roving performance piece for musicians, dancers, and audience-responsive electronics based on themes of insect breeding swarms (mayflies), environmental degradation, and rebirth. The piece sprouted from the idea of a mysterious insect species that develops in the trash we humans discard everyday. They grow and molt and incorporate components of our waste into their bodies. They move and dance, and when the time is right, come together in an apocalyptic swarm.
It featured The Fourth Wall Ensemble and Amorphous Dance Collective, with costumes by Emily Taradash.


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The 1979 Winston GT season was the 9th season of the IMSA GT Championship auto racing series.  It was a series for GTX class Group 5 cars and GTO and GTU class Grand tourer cars.  It began February 3, 1979, and ended November 25, 1979, after fifteen rounds.

Schedule
Not all classes participated in shorter events.  Races marked with All had all classes on track at the same time.

Season results

External links
 World Sports Racing Prototypes - 1979 IMSA GT Championship results

IMSA GT Championship seasons
IMSA GT

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