Answers are grounded in this paper and cite their sources.
A spherical-grid photoelectron spectrometer has been used to measure the ionization potentials of HF, HCl, HBr, HI, F2, Cl2, Br2, and I2. The relative transition probabilities to several of the ionic states are given. There is evidence that the 2Σ+ ionic states in HI+, Cl2+, Br2+, and I2+ are unstable.
No takes yet. Share an insight, caveat, or question.
Frost et al. (1967) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: