Configuration interaction studies of the excited states of water

We report the results of extensive configuration interaction studies on 16 excited states of water. These states can be accurately described as corresponding to excitation from one of the highest two molecular orbitals (1b1 or 3a1) of the ground state into either the 3s or one of the three 3p Rydberg orbitals. The results provide the most accurate and consistent treatment of these states to date (within 0.1 eV for all known transitions) and form a reliable basis for the assignment of the photon and electron impact spectra of H2O.