Deactivation of electronically excited thallium, Tl(6p²P_3/2), in collisions with small molecules

The efficiencies of energy transfer from electronically excited thallium, Tl(6p ²P_3/2), to a variety of collision partners have been measured and compared to similar processes involving iodine, I(5p⁵ 2P_1/2). Several mechanisms are discussed, and the possible role of ionic charge transfer complexes in facilitating such energy transfers assessed. Such complexes appear to play a significant role in the deactivation of Tl(6p ²P_3/2) by molecules with positive electron affinities. The production of electronically excited thallium by energy transfer from O₂(¹Δ_g) is discussed, this latter species being formed chemically in the reaction of electronically excited oxygen atoms, O(2p^{4 1}D₂), with N₂O.