Monte Carlo classical dynamical study of the Cl + Cl2 and I + I2 systems: Vibrational relaxation and atom-exchange reactions

Abstract

The Monte Carlo quasiclassical trajectory method is used to investigate the atom‐exchange reactions and the vibrational relaxation in the systems Cl + Cl₂ and I + I₂. The Cl + Cl₂ system is examined over the temperature range 500–1500°K and initial vibrational states ν = 0, 1, 3, 7, and 14, and the I + I₂ system is examined over the temperature range 700–1500°K and initial vibrational levels ν = 0, 1, 7, 10, 12, and 14. London equation potential‐energy surfaces are employed; the energy barrier to linear configuration atom exchange is zero for Cl + Cl₂ and about 5.9 kcal/mole for I + I₂. The rates of atom exchange for both Cl + Cl₂ and I + I₂ are calculated as a function of temperature and initial vibrational state. Vibrational relaxation rate coefficients are calculated for individual transitions ν→ν′ for both reactive and nonreactive collisions. It is found that both nonreactive collisions and atom‐exchange reactions contribute to the vibrational relaxation.