Model calculations of polarizabilities of polyene chains: Oligomers and infinite polymers

Abstract

In order to find the best methods for calculating the (hyper) polarizabilities of long oligomers and infinite polymers, we first propose in this paper to calculate the linear static electric polarizabilities of regular and alternant polyene chains by using the Hückel approach. For these calculations, the perturbation approach is used to obtain second-order response properties. We have derived this formulation by starting from the polarization propagator within an approximation which consists of projecting the superoperator resolvent form on a basis set of operators composed of only single excitations. For polyenes of different degrees of bond alternation, we obtained in the same Hückel approximation the asymptotic value of the polarizability per unit cell by using the Bloch functions in the Genkin and Mednis technique of calculating polymeric polarizabilities.