H_3PAuR型单核Au(Ⅰ)配合物的结构和非线性光学系数的量子化学计算比较

Quantum Chemistry Calculation on Structures and NLO Cofficients of H_3PAuR Type Mononucleus Au(Ⅰ) Complex

采用量子化学ab initio和DFT中的不同方法和基组对H3PAuR型单核Au(Ⅰ)配合物结构和二阶NLO系数进行计算,探讨不同计算方法和Au基组对计算结果产生的影响.对计算结果分析表明,不同计算方法对Au(Ⅰ)配合物结构和二阶NLO系数影响较大,其中用考虑电子相关效应的DFT-B3LYP和MP2方法优化得到的Au—P配键长比用HF方法的短,相应的二阶NLO系数比HF方法的大2倍左右;同一计算方法下,Au基组中d轨道个数增加优化得到的Au—P配键键长减小;随着Au基组的增大,前线分子轨道能级差减小,其中SDD和CEP-121G基组之间的变化更明显.基组变化对分子二阶NLO系数的影响较小,多数分子Au取不同基组计算的βμ值相差在10%以内.

Different quantum chemical ab initio methods and basis sets were adopted to investigate the structures and second-order nonlinear optical properties of H3PAuR type mononuclear Au （ Ⅰ ） complexes. The influence of different calculation methods and basis sets of Au on the calculation results were also discussed systematically. The results indicate that different methods give rise to a great effect on the structures and secondorder nonlinear optical properties of mononuclear Au （ Ⅰ ） complexes. Herein, the length of coordinative bond of Au--P from HF method is shorter than that from DFT B3LYP and MP2 methods. Moreover, the second-order NLO coefficients obtained by DFT B3LYP and MP2 methods are two times larger than that by HF method. Based on the same methods, the coordinative bond length of Au-P decreased with increasing the number of d orbitals in the basis set of Au. Meanwhile, with increasing the basis sets of Au, the energy gap of frontier molecular orbitals decreased, which can be observed clearly for the SDD and CEP-121G basis sets. However, different basis sets have little influence on the second-order NLO coefficients. The difference of βμ value with different basis sets of Au for most of the molecules is less than 10%.