Fluorescence cross sections and electronic transition moments for the A 2Σ+→X 2Π transition in HCl+ by photoionization. Comparison with the ab initio calculations

The electronically excited HCl+ (A 2Σ+) ions have been produced by the direct photoionization with helium and neon resonance lines. The emission bands A 2Σ+(v′=0–6)→X 2Π (v″=0−2) were detected. The absolute fluorescent cross sections of the transition were determined at 58.4 and 73.6 nm. The ab initio configuration interaction calculations were carried out for the A 2Σ+ and X 2Π states. The excellent agreement between the experimental and ab initio results was obtained for the Franck–Condon factors, electronic transition moments, and potential energy curves.