Isotope Effects on the Energy Flow and Bond Dissociations of Excited α‐Chlorotoluene in Collisions with H2/D2

Abstract

We have studied the vibrational relaxation of excited α‐chlorotoluene and dissociations of CHring and CCl bonds of α‐chlorotoluene in the α‐chlorotoluene + H2/D2 collision at 300 K using classical trajectory procedure. The vibrational energy loss of excited α‐chlorotoluene by the collision of the ground‐state H2/D2 is small, but it increases with increasing the total vibrational excitation, ET. The magnitude of energy loss was significantly larger in the α‐CT + D2 system, especially for values of ET above 30 000 cm−1. Moreover, the vibrational relaxation of α‐CT was found to be primarily because of the CCl vibrational decay. Furthermore, the D2 molecule induced stronger perturbations on the α‐CT molecule, which enhanced the vibrational relaxation of α‐CT. Dissociation probabilities in both systems, which were initially low, rapidly increased with an increase in the total vibrational excitation. The CCl bond dissociation probability was found to be lower than that of CHring at values of ET slightly below 70 000 cm−1, because the probability of the CCl bond gaining sufficient energy for dissociation was low compared to that of the CHring bond. The dissociation probabilities of the CHring and CCl bonds in the α‐CT + D2 collision system were found to be higher than those in the α‐CT + H2 system, because of more efficient perturbation in the former.