Bond-Dependent Thole Model for Polarizability and
Spectroscopy
DelloStrittoMark
L. KleinMichael
BorguetEric
2019
We present a new model for the calculation
of molecular polarizabilities
from effective atomic polarizabilities. This model is based on the
Thole modified dipole interaction model for molecular polarizabilities,
where the total polarizability is computed as a sum of effective atomic
polarizabilities modified by dipoleâ€“dipole interactions. We
extend this model by making the atomic polarizabilities explicit functions
of the interatomic distances, scaling them by the radius of the volume
an atom occupies in a molecule. We use the SCAN functional to show
that this model, denoted TholeL, yields accurate molecular polarizabilities
with little dependence on the training set. We also demonstrate that
the TholeL model yields accurate polarizabilities for configurations
far from the ground state structure for a wide range of molecules.
Finally, we show that the TholeL model can be used to generate accurate
Raman spectra for water, crystalline urea, and urea in water from
ab initio molecular dynamics simulations.