Influence of Highly Efficient Collisions on Vibrational Relaxation of Triplet Acetophenone Molecules

摘要

Parameters of the time-resolved delayed luminescence of acetophenone vapors excited to the S_1 state by a nitrogen laser radiation (#lambda# = 337 nm) are studied as functions of pressure of vapors and foreign gases (He, Ar, Xe, SF_6 or C_2H_4). It is shown that the relaxation of vibrationally-excited triplet molecules occurs via two stages: (1) vibrational equilibration (V-V relaxation) and (2) thermalization (V-T relaxation). The V-V process efficiencies and the average energies <#DELTA#E> transferred in collision are estimated. It is shown that in mixtures of acetophenone and molecular gases the redistribution of vibrational energy over a set of triplet state vibrational levels occurs with a high efficiency, which is typical for supercollisions. Experimental <#DELTA#E> values correlate well with the values predicted by statistical theories of ergodic transfer.