Effects of The Vibrational and Rotational Energy on Reaction Cross- Section in a Classical Trajectory Study of Atom-Diatomic Molecule Collisions

Abstract

Effects of the initial vibrational and rotational energy of a diatomic molecule on reaction rates of atom-diatomic molecule reactions have been studied using classical trajectory calculations. The reaction probabilities, cross-sections and rate constants were calculated using the three-dimensional Monte-Carlo method. Equations of motion, which predict the positions and momenta of the colliding particles after each step in the trajectory, have been integrated numerically by the Runge-Kutta-Gill and Adams-Moulton methods. Morse potential energy surfaces were used to describe the interaction between the atom and each atom in the diatomic molecule. Several atom-diatomic molecule systems were studied. Variation of the reaction cross-section with both vibrational and rotational quantum numbers has been studied. For all systems studied, it was found that the cross-section increases with the vibrational quantum number. However, the effect of rotational quantum number on cross-section varies from one system to another. Results obtained in the present work were compared with experimental data and/or with results obtained theoretically. Good agreements were observed with experimental and with theoretical results obtained by other investigators using different calculation methods.