Energy transfer in A 2Σ+ OH. II. Vibrational

Abstract

Vibrational energy transfer within the A ²Σ⁺ state of OH and OD has been studied. A frequency doubled tunable dye laser excites individual N′, J′ levels in v′=1 or 2, and the intensities of rotationally resolved fluorescence emitted in the presence of collision partners (He, Ar, H₂, D₂, and N₂) furnished state‐to‐state transfer rates. It is found that the transfer rates are strongly dependent on initial rotational level (decreasing as N_i increases), that the final rotational state distributions are near thermal but hot, that isoenergetic transfer is small, and that the magnitudes for transfer 1→0, 2→1, and 2→0 are all similar. The rates themselves are large; for example, with N₂, k_1→0 (N_i=3) =1.7×10⁻¹⁰ cm³ sec⁻¹. The results, taken together, are supportive of a long‐lived collision in which anisotropic attractive forces are of importance in the dynamics of the entrance channel.