Ab initio finite oligomer method for nonlinear optical properties of conjugated polymers: Nonresonant frequency dispersion in polyacetylene.

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. © 1996 American Institute of Physics. [ABSTRACT FROM AUTHOR]