Relaxation processes in excited CO states. I. Spin multiplet relaxation and radiative lifetimes ofCOlpar;d3Dgr;rpar;ngr;equals;5

摘要

Observations made of thed3Dgr;rarr;a3thinsp;Pgr;thinsp;5,0band of CO demonstrate that thed3Dgr;ngr;equals;5level has a radiative lifetime strongly dependent on rotational level. This is a consequence of the interaction betweend3Dgr;ngr;equals;5and the nearbyAthinsp;1Pgr;ngr;equals;1level, which mixes the two states and causes strongd3Dgr;ngr;equals;5rarr;X1Sgr;plus;radiation to compete withdrarr;aradiation as a depopulating mechanism fromd3Dgr;ngr;equals;5. Because of the selection rules governing optical transitions and perturbations, it is only the OHgr; 1 level ofd3Dgr;ngr;equals;5that is strongly perturbed, and relaxation of3Dgr;1to3Dgr;2and3Dgr;3as a function of rare gas collisions has been observed. Relaxation by Ar takes place at close to hard sphere collision frequency, with He being 5.5 times less efficient.