化学学报 ›› 2004, Vol. 62 ›› Issue (16): 1477-1483. 上一篇    下一篇

研究论文

离子对生成反应Li+I2→Li++I2-的理论研究:从头算势能面和反应几率

孙孝敏1, 张君1, 冯大诚1, 蔡政亭1, 边文生2   

  1. 1. 山东大学理论化学研究所, 济南, 250100;
    2. 中国科学院化学研究所分子反应动力学国家重点实验室, 北京, 100080
  • 投稿日期:2003-10-14 修回日期:2004-04-19 发布日期:2014-02-17
  • 通讯作者: zhtcai@sdu.edu.cn
  • 作者简介:蔡政亭,E-mail:zhtcai@sdu.edu.cn
  • 基金资助:
    国家自然科学基金(Nos.20173032,20073024)、高等学校博士点基金资助项目.

Theoretical Study of the Ion-pair Formation Process Li + I2→Li+ + I2-: Ab initio PES and Reaction Probability

SUN Xiao-Min1, ZHANG Jun1, FENG Da-Cheng1, CAI Zheng-Ting1, BIAN Wen-Sheng2   

  1. 1. Institute of Theoretical Chemistry, Shandong University, Jinan 250100;
    2. State Key Labrotaroy of Molecular Reaction Dynamics, Institue of Chemistry, Chinese Academy of Sciences, Beijing 100080
  • Received:2003-10-14 Revised:2004-04-19 Published:2014-02-17

采用QCISD(T)方法进行了构型优化及势能面扫描.电荷布居分析采用QCISD,对Li+I2→Li++I2-离子对生成反应进行了系统的从头算理论研究:(1)构筑了两电子态(离子性2B2态和中性分子2A1态)的完全从头算势能面,找到了两电子态势能面上的最低能量反应途径及两势能曲面的交线,据此确定了离子态与中性分子态之间的最可几交叉半径(Rcmax),计算了该处电子精细结构,得到的电子亲合能和解离能与实验光谱数据相吻合;(2)用Landau-Zener公式计算了离子对生成几率,发现了散射共振态的存在,这一结果与Na+I2→Na++I2-体系非常相似,并比较了可得到的实验数据.

关键词: 从头算两态势能面, 离子对生成几率, 非绝热耦合, 散射共振态

For ion-pair formation process Li+I2→Li ++I2-, the ab initio potential energy surfaces (PES) of two electronic states (ionic 2B2 state and covalent 2A1 state) were constructed by use of QCISD(T) method.Minimum energy reaction path on each PES and the crossing curve of the two-state PES were abstracted.According to the results, the most probable crossing radius (Rcmax) between the ionic and covalent states was determined, and the fine electronic structure on the crossing point was calculated.The electron affinity of I2 molecule and the dissociation energy of I2- anion and the ionization potential of Li atom obtained from present PES are quite in agreement with the experimental and spectrum data.The ion-pair formation probability was calculated using Landau-Zener formula, and from it the scattering resonance state was found, which is similar to the Na+I2→Na++I2- system.

Key words: ab initio potential energy surface of two electronic states, ion-pair formation probability, nonadiabatic coupling, scattering resonance state