Optical Susceptibilities of Polymers: Current-Current versus Dipole-Dipole Correlation
arXiv:cond-mat/9905406 · doi:10.1016/S0375-9601(99)00288-1
Abstract
The static current operator leads to definitional zero frequency divergence and unphysical results in studying nonlinear optical susceptibilities of polymers. A well-defined dipole-dipole correlation is superior to the complicated current-current correlation to solve this problem. As illustrative examples, optical susceptibilities under both SSH and TLM models of trans-(CH)_x are studied. New analytical results are obtained. The reasons of previous improper results are analyzed.