DETERMINATION OF FINE STRUCTURE TRANSITION CROSS SECTIONS OF Rb(7²D) ATOMS INDUCED BY COLLISIONS WITH MOLECULES OF H₂ OR CO

The cross sections for fine-structure transition (FST) of Rb(7²D) atoms induced by collision with molecules of H₂ and CO have been experimentally determined by the method of selective stepwise excitation of Rb atoms and observation of the resulting fluorescence. The cross sections (in units of 10^-14cm²) for Rb(7²D) - H₂ are σ^*_fs(7²D_5/2 → 7²D_3/2) = 0.16±0.03, σ^*｀_fs(7²D_3/2 →7²D_5/2) = 0.24 ±0.05, for Rb(7²D)-CO: σ^*_fs = 0.10±0.06 and σ^*｀_fs = 0.15±0.09. The cross sections σ^*_tr for transfer out of the 7²D doublet were also determined.