Vibrational Relaxation of CO2(0001) in CO2, He, Ne and Ar in the Temperature Range of 300∼140 K

Abstract

The laser-induced fluorescence of CO 2 (00 0 1) has been measured after the pulsed excitation of CO 2 by the HBr chemical laser line of P(6) (υ'=2→υ''=1) which is nearly resonant to the R(20) line of 00 0 0→00 0 1 transition. The deactivation rate of CO 2 (00 0 1) in rare gases of He, Ne and Ar decreases as the temperature is lowered, while its temperature dependence becomes smaller at lower temperatures. In contrast to this, the deactivation rate in CO 2 shows a minimum in the vicinity of 300 K and a negative temperature dependence below 300 K. The former result would be expected supposing that the role of the attractive part of interaction potential increases as the relative kinetic energy of the collision is reduced. Taking this effect into account, however, the latter finding is difficult to be explained by a simple extension of the former collision theory.