HX_2~+(X=Cl,Br)离子的结构与HBr_2~+离子的势能函数

Structures of the HX_2~+(X=Cl,Br) Ions and Analytic Potential Energy Function of the HBr_2~+ Ion

摘要: 选取密度泛函(B3LYP)方法,采取6-311++G(2df,2pd)基组对单态HCl2+与HBr2+离子可能的几何构型进行了优化计算,并求得了Cl2与Br2的质子亲和能及Cl—CIH+与Br—BrH+的键分离能.得到HCl2+离子最稳态为Cs构型,电子态为1A′,平衡核间距为RCIH=0.1315nm,RClCl=0.2022nm,键角∠HClCl=99.4°.HBr2+离子最稳态为Cs构型,电子态为1A,平衡核间距为RBrH=0.1452nm,RBrBr=0.2328nm,键角∠H-BrBr=97.5°,离解能为De=8.208eV,Br—H键伸缩振动频率为2399cm-1,H—Br—Br键弯曲振动频率为706cm-1,Br-Br键伸缩振动频率294cm-1.并首次采用多体项展式理论推导出了基态HBr2+离子的解析势能函数.对应的等值势能图准确再现了HBr2+离子的平衡结构及其离解能;并可由势能图观察到Br(2Pu)+HBr+(X2Πi)→HBr2+(X1A′)反应通道上出现一个鞍点,其位置在RBrBr=0.42nm,RHBr=0.16nm,∠HBrBr=97.5°,V=-5.5eV,垒高约0.53eV.

Abstract: Using density functional(B3LYP) method and the 6-311++G(2df,2pd) basis set,the possible configurations of the single state HCl+2 and HBr+2 ions have been optimized,and the proton affinity of Cl2 and Br2,the bond dissociation energy of Cl—CIH+ and Br—BrH+ have been calculated.The results show that the ground state of HCl+2 ion has Cs symmetry and is in the 1A′ state.The parameters of structure are RCIH=0.131 5 nm,RClCl=0.202 2 nm,∠HClCl=99.4°.The results also show that the ground state of HBr+2 ion has Cs sy...