物理化学学报 >> 1994, Vol. 10 >> Issue (12): 1075-1080.doi: 10.3866/PKU.WHXB19941205

研究论文 上一篇    下一篇

F-N=C→F-C≡N的动力学及产物的振动态分布

李宗和, 吴俊南, 刘若庄, 马思渝, 冯文林, 王梅天   

  1. 北京师范大学化学系量化室,北京 100875
  • 收稿日期:1993-11-16 修回日期:1994-01-29 发布日期:1994-12-15
  • 通讯作者: 刘若庄

Dynamics and Product Vibrational State Distributions of the Reaction of the F-N=C→F-C≡N

Li Zong-He, Wu Jun-Nan, Liu Ruo-Zhuang, Ma Si-Yu, Feng Wen-Lin, Wang Mei-Tian   

  1. Department of Chemistry,Beijing Normal Universtiy,Beijing 100875
  • Received:1993-11-16 Revised:1994-01-29 Published:1994-12-15
  • Contact: Liu Ruo-Zhuang

摘要:

用数值方案,在RHF/3-21G分子轨道从头算法的水平上,得到了氟化异氰FNC到氟化氰FCN重排反应的反应途径(内禀反应坐标IRC).沿着IRC;讨论了反应过程中体系几何构型的变化,计算了沿IRC运动与垂直于IRC简正振动之间的耦合常数(BK,F),各振动模式对应的频率(ωK),使用统一的半经典徽扰和无限级突然(SCP-IOS)近似理论计算了在一定能量下产物的振动分配. 结果表明,在过渡态后,耦合常数(BK,F)的大小强烈地影响产物的振动态分布,另外用传统过渡态、变分过渡态理论及相关的隧道效应校正计算了该反应的速率常数.

关键词: 内禀反应坐标(IRC), 反应速率常数, 产物振动态分布

Abstract:

In this paper , based on ab initio (3-21G) SCF MO with gradient technique, the intrinsic reaction coordinate (IRC) of the rearrangement reaction F-N=C→F-C≡N has been traced by using numerical method. Along the IRC, the variations of the relative positions of different atoms in this system, the coupling constants between the IRC and vibrations orthogonal with it, and the vibrational frequencies have all been investigated. The product vibrational state distributions of the rearrangement reaction have been calculated at different energies by using the semiclassical perturbation (SCP)-infinite order sudden (IOS) approximation, the calculated results of the distributions are affected greatly by the magnitude of coupling constants (BK,F). The theoretical rate constants in the conventional transition state theory, variational transition state theory and with tunneling corrections have also been calculated in this paper.

Key words: Intrinsic reaction coordinate(IRC), Reaction rate constant, Product vibrational state distribution