Temperature dependence of vibrational relaxation from the upper vibrational levels of HF and DF

Abstract

A kinetic model of infrared laser-induced fluorescence experiments has been used to simulate quenching coefficients between 300 and 2400 K for the vibrational relaxation of HF(v1) and DF(v1) by HF(v2=0) and DF(v2=0). This rotational nonequilibrium model is based on the predicted energy-transfer mechanisms in hydrogen–fluoride and deuterium–fluoride systems reported earlier by Wilkins. The deactivation rates for the V→R processes for HF(v1)+HF(v2=0) and their isotopic analogs are predicted to scale as vn with n varying from 2.3 to 1.6 as v varies from 2 to 6. These quenching coefficients for V→R processes from the upper vibrational levels are predicted to have a temperature dependence very similar to that for V→R relaxation from the v=1 level. The results are discussed in relation to V→V energy transfer and V→R intramolecular energy conversion.