<i>Ab</i> <i>initio</i> finite oligomer method for nonlinear optical properties of conjugated polymers: Nonresonant frequency dispersion in polyacetylene

Abstract

Nonlinear optical properties of the linear polyenes C4H6 through C30H32 are calculated at frequencies below the first resonance using ab initio time-dependent Hartree–Fock theory. The results are used to determine accurate values for the infinite polymer, polyacetylene, by means of a new extrapolation method. Dispersion coefficients describing the low frequency behavior are obtained for the largest oligomer.