Theoretical study of the rovibrational spectrum of H2O–H2

In this paper we report transition frequencies and line strengths computed for H(2)O-H(2) and compare with the experimental observations of [M. J. Weida and D. J. Nesbitt, J. Chem. Phys. 110, 156 (1999)]. To compute the spectra we use a symmetry adapted Lanczos algorithm and an uncoupled product basis set. Our results corroborate the assignments of Weida and Nesbitt and there is good agreement between calculated and observed transitions. Possible candidates for lines that Weida and Nesbitt were not able to assign are presented. Several other bands that may be observable are also discovered. Although all the observed bands are associated with states localized near the global potential minimum, at which H(2)O acts as proton acceptor, a state with significant amplitude near the T-shape secondary potential minimum at which H(2)O acts as proton donor is identified by examining many different probability density plots.