Vibrational relaxation of KrF^* and XeCl^* by rare gases

A steady-state, chemiluminescence technique has been used to measure effective rate constants for vibrational relaxation as a function of vibrational level for KrF^* in collisions with He, Ne, and Ar and XeCl^* with Ar. The effective rate constants reported include contributions to relaxation due to intersystem crossing between the B and C states, in addition to direct relaxation within the B state. The relevance of these results to the understanding of previous measurements in KrF and XeCl lasers is discussed.