尿素和硫脲分子非线性光学性质的从头算研究

Ab initio study of the nonlinear optical susceptibilities of urea and thiourea

在B3LYP/6-31++G(2DF,2PD)水平优化气相中的尿素和硫脲分子构型,得到C2点群的非平面分子.对此构型的尿素和硫脲分子用CPHF和FF方法进行了非线性光学性质的计算,比较了尿素和硫脲非线性光学性质,讨论了极化函数、弥散函数和相关效应对(超)极化率的影响,还与固定C2V对称相同水平优化得到的平面分子计算结果进行了比较.

Opt the geometries of urea and thiourea in gas phase at B3LYP/6-31＋＋G（2DF,2PD） level, their simmetries are C2 point group. There nonlinear optical（NLO） susceptibilities are calculated by CPHF and FF methods, and the differences between urea and thiourea are reported.The effections of the polarization functions, the diffusion functions and electron correlation are discussed. And the differences of NLO susceptibilities between C2V point group molecules which are opted by defining there geometries as C2V and the C2 ones are reported.