Rate Coefficients of Exchange Reactions in Air and Carbon Dioxide

Abstract

A simple theoretical Treanor-Marrone model is generalized to calculate state-resolved exchange reaction rate coefficients in air and carbon dioxide. An analytical dependence of the activation energy on the vibrational energy of the reactants and products is obtained for the Zeldovich reactions. This allows taking into account the vibrational excitation of NO molecules formed as a result of exchange reactions. The state-resolved reaction rate coefficients calculated using the proposed model are in good agreement with the latest data of quasi-classical trajectory calculations. The developed approach is applied to calculate the state-resolved exchange reaction rate coefficients in carbon dioxide. The effect of the model parameter on the reaction rate coefficients is estimated. Multi-temperature rate coefficients of exchange reactions in CO2 are calculated under conditions characteristic for shock waves on the basis of vibrational distributions taking into account fast intermode VV exchange between symmetric and bending modes and slow VT relaxation in bending and antisymmetric modes. The effect of vibrational excitation of various modes on the reaction rate is discussed.