Calculation of the second-order electronic polarizabilities of some organic molecules. Part 1

Abstract

A version of the CNDO/S method has been re-parametrized by correlating computed and measured dipole moments and transition wavelengths for a range of organic conjugated molecules. The method has then been used to calculate the hyperpolarizability tensor, βijk, in the form related to second-harmonic generation, for an extended set of molecules of similar type. A good correlation between theory and experiment has been found. The convergence of the excited-state perturbation expansion used in the calculation of the tensor has been extensively investigated.