Rates and pathways of vibrational selfhyphen;relaxation of HF(v=2) between 300 and 700 K

摘要

The temperature dependencies of the total selfhyphen;relaxation rate constants for the vibrational deactivation of HF(v=2) and HF(v=1) and the statehyphen;tohyphen;state vibrationhyphen;tohyphen;vibration (Vndash;V) and vibrationhyphen;tohyphen;translationhyphen;andhyphen;rotation (Vhyphen;T,R) energy transfer components of the HF(v=2) selfhyphen;relaxation process are measured using the overtone vibration excitationhyphen;laser double resonance technique. The total selfhyphen;relaxation rate constants vary inversely with temperature. The much weaker temperature dependence of HF(v=2) selfhyphen;relaxation compared to that of HF(v=1) arises from the significant role of the Vndash;V energy transfer route. Competition between energetics and collision duration results in a weaker inverse variation with temperature for the slightly endothermic Vndash;V route than for the exothermic Vhyphen;T,R route for HF(v=2). The branching ratio for Vndash;V energy transfer increases slightly with temperature and the data suggest that two quantum relaxation processes constitute no more than 10percnt; of the total selfhyphen;relaxation of HF(v=2). The available temperature dependence data on selfhyphen;relaxation of HF(v=1ndash;5) form a consistent picture in which the energetics of the Vndash;V and Vhyphen;T,R relaxation pathways control their relative contributions to the total energy transfer.