聚乙炔链二阶超极化率的构型、基组和相关效应的从头算研究  

The study of the impact of geometries,basis sets and electron correlation on second haperpolarizability of infinite polyyne chain

作　　者：何云清[1] 丁涪江[1] 

机构地区：[1]四川师范大学化学学院,成都610066

出　　处：《原子与分子物理学报》2006年第3期479-484,共6页Journal of Atomic and Molecular Physics

基　　金：四川省教育厅重点基金(2003A087)

摘　　要：在RHF/STO-3G和RHF/6-31G水平上优化聚乙炔链,计算了聚乙炔链的轴向线性极化率αzz和二阶超极化率γzzzz,最多计算到27个—C≡C—结构单元,利用不同电场下分子的E、μ、α、β获得了RHF水平的稳定可靠的γzzzz;用不同电场下的能量得到了MP2/6-31G水平的γ值,计算到19个结构单元.在此基础上根据选定的目标函数、拟合函数和拟合数据范围,外推出可信的超极化率的极限值,讨论了优化水平和基组对α和γ计算值的影响.Ab initio calculations are reported for the static longitudinal polarizability αxx and the second hyper-olarizability γxxxx of the polyyne chain at different levels of approximation of including geometries, basis sets, and electron correlation. The geometries of all studed moleeules are optimized at RHF/STO - 3G or RHF/6 - 31G levels. The largest molecule calculated is H-（C≡C）27-H for RHF and H-（C≡C）19-H for MP2 . The values per C≡C unit are accurately extrapolated to the infinite chain limit at RHF and MP2 levels. The influenees of optimized levels, basis sets and electron eorrelation on α and γ are discussed .

关 键 词：极化率 从头算 聚乙炔链 极限 拟合 

分 类 号：O561[理学—原子与分子物理]