Abstract: Collinear exact quantum method is used to study the vibrational deactivation process of H+ClH(v≤3) on a newly-fitted ab initio potential energy surface.The reactive and nonreactive inelastic probabilities are obtained, which are found to oscillate with energy and exhibit some vibrationally nonadiabatic behavior.We conclude that, Hatoms are not very efficient deactivators of vibrationally excited HCl, and in the producing vibrational deactivation the nonreactive inelastic mechanism dominates over the reactive one at lower energies while reactive collisions become more important if the energy is high enough.Many conclusions from this work are shown to be in qualitative agreement with those from some previous literatures.

Key words: Quantum scattering, Vibrational deactivation, Chemical laser, H₂Cl system