Collision-induced CH bond dissociation in highly excited toluene

The bond dissociation of highly excited toluene colliding with argon has been studied by use of classical trajectory procedures. All 39 stretches and bends of toluene are included in the model. Both methyl and adjacent ring CH bonds, each with the initial vibrational energy 0.10 eV below the dissociation threshold, are in interaction with Ar. The dissociation probabilities are PCHmethyl = 0.14 and PCHring = 0.19 at 300 K. The CHmethyl bond dissociation is a result of the Ar–CHmethyl collision transferring a large amount of energy (≫kT) via the T → V pathway. The activation of CHring toward dissociation occurs through a series of small steps gaining energy intramolecularly from the methyl end. The Ar–CHring interaction is unimportant in transferring energy to the CHring stretch and in turn causing the bond dissociation.