  In recent decades, computer simulations have found increasingly widespread
use as powerful tools of studying phase transitions in wide variety of systems.
In the particular and very important case of aqueous systems, the commonly used
force-fields tend to offer quite different predictions with respect to a wide
range of thermodynamic and kinetic properties, including the ease of ice
nucleation, the propensity to freeze at a vapor-liquid interface, and the
existence of a liquid-liquid phase transition. It is thus of fundamental and
practical interest to understand how different features of a given water model
affect its thermodynamic and kinetic properties. In this work, we use the
forward-flux sampling technique to study the crystallization kinetics of a
family of modified Stillinger-Weber (SW) potentials with energy ($\epsilon$)
and length ($\sigma$) scales taken from the monoatomic water (mW) model, but
with different tetrahedrality parameters ($\lambda$). By increasing $\lambda$
from 21 to 24, we observe the nucleation rate increases by 48 orders of
magnitude at a supercooling of ${\zeta}=T/T_m=0.845$. Using classical
nucleation theory, we are able to demonstrate that this change can largely be
accounted for by the increase in $|\Delta\mu|$, the thermodynamic driving
force. We also perform rate calculations in freestanding thin films of the
supercooled liquid, and observe a crossover from a surface-enhanced
crystallization at $\lambda = 21$ to a bulk-dominated crystallization for
$\lambda\ge22$.

Statistical Mechanics;Soft Condensed Matter