NiH_2分子的结构及其势能函数

The molecular structure and potential energy function for NiH_2 system

应用群论及原子分子反应静力学方法推导了NiH2 分子基态的电子态及其离解极限 ,在MP2 /6 -311G 水平上 ,优化出NiH2 (X3 Δg)分子稳定构型为D∞h,其平衡核间距Re=0 .15 73nm、∠HNiH =180 .0 0° ,同时计算出振动频率 :对称伸缩振动频率ν1=2 0 0 0cm-1,弯曲振动频率ν2 =72 1cm-1和反对称伸缩振动频率ν3 =1875cm-1。在此基础上 ,使用多体项展式理论方法 ,导出了基态NiH2 分子的全空间解析势能函数 ,该势能函数准确地再现了NiH2 (D∞h)平衡结构。

In the present paper, firstly, the electronic state and reasonable dissociation limits of NiH 2 are correctly determined based on group theory and atomic and molecular reaction statics. Moreover, using the MP2 and basis 6-311G  , we have optimized the equilibrium geometry for the ground state X 3Δ g of NiH 2, which is D ∞h . The equailibrium geometry, dissociation energy and harmonic frequencies for NiH 2 have been calculated. The results show that R e (NiH)=0.157 3 nm, D e (NiH 2)=9.846 eV, and ν 1,ν 2 and ν 3 are 2 000,721 and 1 875 cm -1 ,respectively. Finally, an analytical potential energy function for the ground state X 3Δ g of NiH 2 has been derived using many-obdy expansion method, Then, the potential energy function is successfully used for describing the equilibrium geometry of NiH 2.