looking for the absorption spectrum of polyene

I am looking for the absorption spectrum of linear polyenes (1,3,5-hexatriene, 1,3,5,7-Octatetraene, 1,3,5,7,9-decapentaene, etc..) in the range of UV and Visible light wavelength.


I see the data at the 2nd page of the PDF (\*1). In the table, I see the max absorption wave length for hexatriene is 268nm.





| name | $\lambda\_{max}$ |
| --- | --- |
| ethylene | 163nm |
| butadiene | 217nm |
| hexatriene | 268nm |
| octatetraene | 304nm |



But I see another webpage(\*2) says hxatriene's wave length is 258nm.



```
The absorbance due to the π – π* transition in 1,3,5-hexatriene, for example, occurs at 258 nm.

```

Where do you look for linear polyenes absorption spectrum data?


(\*1) <https://www.chem.purdue.edu/courses/chm424/Handouts/14.2%20Alkenes%20and%20Aromatics.pdf>


(\*2)
<https://courses.lumenlearning.com/suny-mcc-organicchemistry/chapter/interpreting-uv-spectra/>


