Calculation of macroscopic linear and nonlinear optical susceptibilities for the naphthalene, anthracene and meta-nitroaniline crystals

The macroscopic first- to third-order susceptibilities of naphthalene, anthracene and meta-nitroaniline (mNA) are calculated using a rigorous local field approach. Molecular (hyper)polarizabilities used as input are determined by density functional theory calculations with specially designed basis sets and for mNA also by MP2 calculations with the 6-31++G** basis set. In the case of mNA, the permanent electric local field due to the surrounding dipoles in the crystal is taken into account for the first- and second-order susceptibility by a self-consistent approach. The molecular dipole moment and first hyperpolarizability of mNA are drastically changed by the permanent local field. In all cases the calculated first-order susceptibility compares very favorably with experimental data, if the molecular response is distributed over all heavy atoms in the molecules. Similarly, the calculated second-order susceptibility for mNA is in good agreement with available experimental data, if the same distribution scheme is used and the permanent local field is taken into account properly. This implies that accurate values for the molecular second-order hyperpolarizability gamma have to be available. The anisotropic Lorentz field factor approximation yields results that are only slightly worse than the best ones of the rigorous local field theory for the first-order susceptibilities, but fails for the second-order susceptibility of mNA, due to its incapability to describe the large effect of the permanent local field on the first-order hyperpolarizability beta. (C) 2000 Elsevier Science B,V, All rights reserved.