摘要
用量子化学从头计算方法研究环二磷氮的模型化合物(H3PNH)2时发现,如果不在基组中加入磷的d函数,环二磷氮中的P—N竖键将破裂.为检验磷的d函数的作用,提出在分子环境中的分子片轨道的分析方法.先将(H3PNH)2分子分成4个分子片(两个PH3和两个NH),分别计算在分子环境中的各个分子片轨道,再用分子片轨道为基组成整个分子轨道.在分子轨道中,含磷的d函数的分子片轨道的成分很少,剔除之后对优化的键长也影响不大.于是得出结论,磷的d函数只起极化函数的作用,而不是价轨道.
Using (H_3PNH)_2 as a model compound, we examined the role of phosphorus d functions on the optimized stability of P—N bonds in cyclodiphosphonitrigen molecule. The ab initio calculation with phosphorus d functions gives a correct P—N bond length, while the calculation without d functions causes the break of the P—N bond. The role of d functions is studied by the method of polarized fragment orbital analysis. The whole molecule (H_3PNH)_2 is divided into two fragments of H_3P and two fragments of NH. Then the polarized fragment orbitals in molecule(FOM) are calculated by 6-31G* basis set. The optimized P—N bond lengths are close to the result of RHF/6-31G*. The components of the fragment orbitals containing phosphorus d functions are very small in the whole molecular obtitals. According to our analysis on fragment orbital in the molecule, phosphorus d functions are only polarization functions.
出处
《四川师范大学学报（自然科学版）》
CAS
CSCD
2004年第5期520-522,共3页
Journal of Sichuan Normal University（Natural Science）
基金
四川省教育厅重点科研基金资助项目
关键词
D轨道
化学键
极化函数
从头算
d orbital
Chemical bond
Polarized function
Ab initio calculation
