Temperature dependence of the vibrational relaxation of CO (v=1) by NO, O2 and D2, and of the self-relaxation of D2

Rate constants for the vibrational deactivation of CO(v=1) by NO, O2 , and D2 have been measured as a function of the temperature using the laser-induced vibrational fluorescence technique. In the temperature range from 100 to 700 °K considered in our experiments, far-from-resonance V-V energy transfers occur between CO and the collision partners. In CO-NO and CO-O2 samples, the CO fluorescence decay curves are single exponentials; only the total de-excitation rates ??CO-M = kCO-M + kCOM of CO(v=1) by M=NO or O2 may be experimentally deduced, kCO-M being the V-V transfer rate and kCOM the V-TR de-excitation rate. In the CO-D2 system, the fluorescence exhibits a double exponential decay; the V-V transfer rate kCO-D2 is found to be much greater than the V-TR de-excitation rate kCOD2 , and the self-relaxation rate kD2 of the deuterium has also been deduced from measurements. The V-V transfer rates kCO-M calculated from a semiclassical method derived from that of Shin, and using a Morse potential, have been compared to the experimental results.