Rotational line profile in the He I excited photoelectron spectrum of the X 2B1 [v′=(0,0,0)] state of H2O+

A photoelectron spectrum of the X 2B1 [v′=(0,0,0)] state of H2O+ has been recorded, excited with He I radiation. The line profile exhibits extensive rotational structure, and a simple analysis based on the ground-state rotational population is used to interpret the spectrum. Judging from this analysis, c-type transitions account for the dominant part of the intensity.