Ne原子的精确二阶超极化率  

Accurate second hyperpolarizabilities of Ne atom

作　　者：丁涪江[1] 刘柳斜[1] 

机构地区：[1]四川师范大学化学系,四川成都610061

出　　处：《化学研究与应用》2004年第6期778-780,共3页Chemical Research and Application

基　　金：四川省教育厅重点课题资助项目(2003A087)

摘　　要：为了获得精确的Ne原子的二阶超极化率,基组必须包括三部分φ=φ(0)+φ(1)+φ(2)。其中φ(0)由s,p函数组成,必须能较完备地描述无外电场时原子的波函数,使无微扰能量E0接近Hartree Fock极限值,同时对远离核的区域的电子云有较好的描述。φ(1)由d函数组成,必须能较完备地描述外场引起的一阶微扰,使极化率α接近Hartree Fock极限值。φ(2)由f函数组成,必须能较完备地描述外场引起的二阶微扰,使超极化率γ接近Hatree Fock极限值。基组的三部分依次分别对EO,α和γ进行优化,从而排除了基组选择过程中的任意性,使计算结果随着基组的扩大而无限趋近Hartree Fock极限值。用35s20p10d7f基组的计算结果是γ(SCF)=68 83,可用来纠正数字轨道的结果。用其收缩后的基组17s11p10d7f计算的相关水平的结果与实验值符合。In order to obtain accurate second hyperpolarizability of Ne atom,a basis set must be used,which contains three parts,φ=φ^((0))+φ^((1))+φ^((2))·φ^((0))consists of s and p-type functions and should be able to express the accurate unperturbed wave function.φ^((1))consists of d-type functions and φ^((2))consists of f-type functions,they should be able to express the first and second perturbed wave functions caused by a uniform electric field respectively.The even-tempered expansions are used for this aim.In light of the importance of sp,d ,and f functions for E_0,E_2,E_4 respectively,exponents for each of these symmetries are optimized for the corresponding property,E_0,α and γ respectively.Our calculation shows that 35s20P10d7f basis set is suitable.According to our calculation with this basis set the Hartree-Fock limit value of second hyperpolarizability of Ne atom should be 68.83.It is more reliable than numerical SCF value 70.0.CCSD(T)calculation with contractive basis set 35s20p10d7f/17s11p10d7f gives the second hyperpolarizability of Ne atom 113.4,which is in agreement with experimental results.

关 键 词：超极化率 Hartree-Fock极限 NE原子 从头算 

分 类 号：O641.121[理学—物理化学]