Dynamics of Collision - Induced Energy Flow and Bond Disssociation in Highly Excited Toluene

초록

The time evolution of intramolecular energy flow and dissociation of highly excited CH bonds in toluene has been studied at 300K by use of classical dynamics procedures. The model consists of the incident atom Ar interacting with the methyl CH and the adjacent ring CH, which are coupled through intermediate stretching and bending modes. Either methyl CH or ring CH is initially placed in a highly excited state near the dissociation threshold, while all other medes are maintained in the ground state. The ensemble - averaged energy loss by the excited methyl CH is a factor of ten higher than that by the excited ring CH. The dissociation of the excited methyl CH bond, which occurs on a subpicosecond time scale, is found to be far more favorable than that of the excited ring CH. Intramolecular flow of the energy deposited in the ground state methyl CH on collision to the highly excited ring CH is efficient, and the amount is large enough to cause ring CH bond dissociation in a strong collision. Energy flew in the reverse direction is found to be inefficient, and there is no evidence if th highly excited methyl CH dissiciating when AR interacts with the ground state ring CH.