Calculations of induced moments in large molecules. II. Polarizabilities and second hyperpolarizabilities of some polyenes

Coupled SCF perturbation theory has been used to calculate the polarizability α and second hyperpolarizability γ of a number of polyenes. An extended basis CNDO wave function has been employed. Our computational approach is based on optimizing the exponents of a small basis set with respect to the experimental values of α and γ of ethylene. We have chosen this scheme having considered in detail several other options. Our results are in reasonable agreement with the limited number of experimental values available for these molecules.