Infrared-ultraviolet double resonance studies of fast vibrational energy transfer in D2CO

Collision-induced V-V energy transfer between different vibrational modes of a small polyatomic molecule in the gas phase generally occurs on the time scale of 101-103 gas-kinetic collisions. The authors' infrared-ultraviolet double resonance (IRUVDR) experiments have demonstrated that collisional V-V transfer between the ν6 (in-plane wag, 989-cm-1) and ν4 (out-of-plane bend, 938-cm-1) vibrational modes of D2CO is remarkably rapid, occurring with approximately gas-kinetic efficiency. The general IRUVDR excitation scheme employed in this context is illustrated. Earlier studies of D2CO/D2CO collisions have now been extended to a variety of collision partners (He, Ar, CH4, N2, N2O), providing some control of the relative rates of ν6 → ν4 transfer and of rotational relaxation with respect to quantum numbers J and Ka