VIBRATIONAL DEPHASING EFFECTS AND MOTIONAL NARROWING IN ISOTROPIC RAMAN-Q BRANCH OF HD

Important motional narrowing has been previously experimentally observed by Dion and May in the isotropic Raman Q branch of pure gaseous HD in the fundamental vibrational band. A recent theoretical calculation of the present authors, in good agreement with these experiments, has shown that for pure HD only rotational mechanisms are efficient. In this paper, an infinite order treatment of the vibrational dephasing effects for HD perturbed by rare gases indicates an important role of these last effects in the broadening of the individual lines (particularly in the 0-2 band) leading to a significant decrease of the motional narrowing in the resulting band profile at high density. © 1978.