Calculating the second-order nonlinear optical susceptibilities of 3-methyl-4-nitropyridine N-oxide, 2-carboxylic acid-4-nitropyridine-1-oxide, 2-methyl-4-nitroaniline, and m-nitroaniline crystals

The static and the second harmonic generation second-order nonlinear susceptibilities, ≁⁽²⁾, of 3-methyl-4-nitropyridine N-oxide, 2-carboxylic acid-4-nitropyridine-1-oxide, 2-methyl-4-nitroaniline, and m-nitroaniline crystals are calculated using a model that combines accurate ab initio molecular properties with an electrostatic interaction approach to account for the crystal packing effects. The impact of the way to distribute the molecular polarizabilities on the final second-order nonlinear susceptibilities is highlighted, whereas the frequency dispersion of the macroscopic and molecular responses is addressed. This approach is shown to reproduce experimental data, at least in what concerns the relative amplitude of ≁⁽²⁾.