Vibronic transition moments and line intensities for H 2O +

Abstract

Ab initio calculations of the electronic dipole moment components for the A ̃ 2A 1 and X ̃ 2B 1 electronic states and the electronic transition moment for the A ̃ 2A 1 – X ̃ 2B 1 transition of H 2O + have been carried out. Parameterized analytical functions have been fitted through the computed ab initio data points, and the resulting dipole moment and transition moment surfaces have been used, along with potential energy surfaces derived from the ab initio results of Brommer et al. [J. Chem. Phys. 98 (1993) 5222], to simulate H 2O + spectra and to generate an extensive set of vibronic transition moments for the A ̃ – X ̃ and X ̃ – X ̃ band systems of H 2O +. The work is made with the dual purpose of facilitating further assignments of high-resolution spectra [J. Mol. Spectrosc. 219 (2003) 258] and of allowing cometary spectra of H 2O + to be simulated [Ap. J. 574 (2002) L183].