On the discrepancy between theoretical calculation and experimental observation of second hyperpolarizability of furan homologues

Frequency dispersion of second hyperpolarizability of furan homologues is c alculated by the time-dependent Hartree-Fock (TDHF) method. Using the calcu lated results, the most reliable theoretical values for the second hyperpol arizability are estimated including both effects of electron correlation ac id frequency dispersion with the comparison of several approximation method s. The estimated values are compared with the observed values measured by t he optical Kerr effect (OKE) method. It is found that by inclusion of the e ffect of frequency dispersion the calculated results approach more closely to the observed values especially for the molecules with heavier hetero ato ms like thiophene, selenophene or tellurophene. (C) 2000 Elsevier Science S .A. All rights reserved.