Study of the Water Molecule in the Gaseous Phase Excited States of H₂O, H₂O⁺ and H₂O⁻

A short account of the electron configuration of water, including symmetry properties, is given. These simple considerations permit the explanation of the results of photoelectron spectroscopy experiments and photoionization experiments; the 2 B 2 state of H 2 O + is predissociated. Excited states of water are all repulsive or predissociated, the more important fragments being OH 2 τ, OH 2 Σ + and O. Some repulsive states of H 2 O − are known, but the important low‐lying 2 A′ state is unknown.