Energy transfer in <i>A</i> 2Σ+ OH. I. Rotational

Abstract

We have used a frequency doubled, tunable dye laser to excite individual v′, N′, J′ levels of the A 2Σ+ state of the OH molecule. The fluorescence emitted in the presence of known pressures of various fill gases has permitted the determination of collisionally induced population changes, and hence state-to-state energy transfer rates. Here are reported results on rotational energy transfer within v′=0, using six different initially pumped levels for N2 as a collision partner, and two each for H2 and Ar. It is found that the rates are fast (5×10−10 cm3 sec−1 for a typical total transfer rate with N2), that a process having ΔN =ΔJ occurs faster than one where ΔN≠ΔJ, and that multiquantum transfer rates are nearly as large as single quantum transfer rates.