Trajectory Calculations for Collisional Energy Flow and Bond Dissociation in Excited Toluene

초록

We have studied the time evolution of both intermolcular and intermolcular energy flow and CJ bond dissociation in the toluene - Ar collision system at 300K using classical trajectory prcedures. The Collision system consists of the interation zone, where the CH(methyl) - Ar and CH(ring) - Ar interactions tatke place, and the inner zone, which includes 13 stretches and 24 bends in the region beyond the interaction zone. The collision systems considered are (i) the methyl CH bond highly excited, (ii) the ring CH highly excited, and (iii) both CH highly excited. Energy transfer to the highly excited methyl CH bond is far more efficient than that to the highly excited ring CH bond, thus leading to bond dissociation more efficiently is system (i) than in system (ii).When both bonds are highly excited, system (iii), the ring CH dissociation rete constants are in oder fo 10(12)s(-1). bond dissociation as well as energy gained by toluene is largely controlled by the CH(methyl)-Ar interaction. Collision - induced energy flow from the highly excited CH(methyl) to the CH(ring) region, especially the CCH(ring) bend, in the interation zone is much more dfficient compared to that of the reverse process, where CH(methyl) is highly excited or in the ground state. The energy from the highly excited CH bonds preferntially deposits in bending modes, especially those tn the interaction zone. The energy gained by some ring CC stretches in the inner zone is found to be significant, but energy transfer to ring CH strecthes is extremely inefficient.