若干有机共轭分子三阶非线性光学系数和链长的关系

我们以INDO/SDCI方法为基础, 利用完全态求和公式, 计算了多烯烃和联苯类分子的三阶非线性光学系数γ(0,0,0,0)和γ(-ω,ω, -ω,ω)。研究了γ与共轭分子链长的关系及其与外场频率的关系, 认为在链不十分长时γ与链长的三次方成正比。γ的大小微观上与电子的离域作用有关。

The length dependence of the nonlinear third-order optical susceptibilities of some conjugated organic molecules

On the basis of INDO/SDCI method, using sum-over-states formula, the nonlinear 3rd-order optical susceptibilities g(0,0,0,0) and g(-w,-w,-w,-w) of polyenes and poly-p-phenyls were calculated The mol. length dependence and the effect of frequency of external field for g showed that g(0,0,0,0) were proportional to the third-power of the lengths, within a certain range, and was relevant to the electronic delocalization in micromechanism.