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

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Rate constants for the vibrational de-excitation 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 χCO–M=kCO–M+kMCO of CO(v=1) by M=NO or O2 may be experimentally deduced, kCO–M being 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 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.