A strong collision partner dependence for vibrational energy transfer in benzene and benzene- d6. He versus D 2

Abstract

State-to-state branching ratios are reported for vibrational energy transfer in benzene and benzene- d 6 due to collisions with D 2 and with He in a supersonic free jet expansion. In both the benzene and benzene- d 6 experiments the initial vibrational level pumped was 6 1. The state-to-state branching ratios are different for D 2 compared with He in C 6H 6 and in C 6D 6. In particular, there is a significant increase in transfer to the 0 0 level for D 2 compared with He. It is postulated that this may be due to the small moment of inertia of D 2, which makes V→R transfer an important mechanism for this collision partner.