Abstract:

In this paper, based on ab initio with gradient technique, the intrinsic reaction coordinate (IRC) of the reaction CN+H2→H+HCN has been traced by using numerical method. Along the IRC, the coupling constants between the IRC and vibrations orthogonal to it, and the vibrational frequencies have all been investigated. The theoretical rate constants for vibrationally excited reactants nCN =1 or nCN = 0 in the conventional transition state theory, variational transition state theory and with tunneling corrections have been calculated. They are in good agreement with experimental results. HCN(nCN=1, nCH=1)+H→CN+H2 reaction rate constants have also been calculated in this paper, and the theoretical results are for experimental reference only.

Key words: Cyanide, Intrinsic reaction coordinate(IRC), Reaction rate constant, State-selected reaction