title: A new ab initio ground-state dipole moment surface for the water molecule.
abstract: A valence-only (V) dipole moment surface (DMS) has been computed for water at the internally contracted multireference configuration interaction level using the extended atom-centered correlation-consistent Gaussian basis set aug-cc-pV6Z. Small corrections to these dipole values, resulting from core correlation (C) and relativistic (R) effects, have also been computed and added to the V surface. The resulting DMS surface is hence called CVR. Interestingly, the C and R corrections cancel out each other almost completely over the whole grid of points investigated. The ground-state CVR dipole of H(2) (16)O is 1.8676 D. This value compares well with the best ab initio one determined in this study, 1.8539+/-0.0013 D, which in turn agrees well with the measured ground-state dipole moment of water, 1.8546(6) D. Line intensities computed with the help of the CVR DMS shows that the present DMS is highly similar to though slightly more accurate than the best previous DMS of water determined by Schwenke and Partridge [J. Chem. Phys. 113, 16 (2000)]. The influence of the precision of the rovibrational wave functions computed using different potential energy surfaces (PESs) has been investigated and proved to be small, due mostly to the small discrepancies between the best ab initio and empirical PESs of water. Several different measures to test the DMS of water are advanced. The seemingly most sensitive measure is the comparison between the ab initio line intensities and those measured by ultralong pathlength methods which are sensitive to very weak transitions.
authors.affiliation: Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Lodi
authors.forename: Roman N
authors.initials: RN
authors.lastname: Tolchenov
authors.forename: Jonathan
authors.initials: J
authors.lastname: Tennyson
authors.forename: A E
authors.initials: AE
authors.lastname: Lynas-Gray
authors.forename: Sergei V
authors.initials: SV
authors.lastname: Shirin
authors.forename: Nikolai F
authors.initials: NF
authors.lastname: Zobov
authors.forename: Oleg L
authors.initials: OL
authors.lastname: Polyansky
authors.forename: Attila G
authors.initials: AG
authors.lastname: Császár
authors.forename: Joost N P
authors.initials: JN
authors.lastname: van Stralen
authors.forename: Lucas
authors.initials: L
authors.lastname: Visscher
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D004583:Electrons; D004735:Energy Transfer; D006859:Hydrogen / Q000737:chemistry; D008958:Models, Molecular; D010100:Oxygen / Q000737:chemistry; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D006859:Hydrogen; D010100:Oxygen