MEAN ENERGY-TRANSFER WITHIN THE SEQUENTIAL DIRECT ENCOUNTER MODEL - TEMPERATURE-DEPENDENCE OF (DELTA-E)

The model of energy transfer in collisions of atoms with vibrationally excited polyatomic molecules suggested recently by the present author s (J. Phys. Chem. 1993, 97, 9397) and based on consecutive direct enco unters is generalized. Incorporation of the lifetime distribution of c ollisions into the Landau-Teller model of the description of the energ y transfer in a single encounter yields a general formula for the temp erature dependence of the mean energy, [Delta E], transferred in a col lision. This formula takes into account the interplay between the posi tive temperature dependence originating from the energy-gap law and th e negative temperature dependence which is related to the collision li fetime. Good agreement of the temperature dependence of [Delta E] betw een the present model and trajectory calculations is obtained.