Energy transfer in A 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.