Electrostatic modeling of the linear optical susceptibilities of 2-methyl-4-nitroaniline, m-nitroaniline, 3-methyl-4-nitropyridine N-oxide and 2-carboxylic acid-4-nitropyridine-1-oxide crystals

An electrostatic interaction scheme is applied to evaluate the macroscopic linear susceptibilities of 2-methyl-4-nitroaniline, m-nitroaniline, 3-methyl-4-nitropyridine N-oxide and 2-carboxylic acid-4-nitropyridine-1-oxide crystals. The molecular polarizabilities have been determined from first principles calculations while a distribution scheme is employed to evaluate the Lorentz-factor tensors. It is shown that when employing an appropriate distribution scheme, where the molecules are divided in polarizable sites placed on each heavy atom, this approach reproduces well the experimental crystal linear susceptibilities and its frequency dispersion. Moreover, averaging the Lorentz-factor tensors over the submolecules has only a weak impact on the agreement with experiment.