title: Communication: VSCF/VCI vibrational spectroscopy of H7O3+and H9O4+using high-level, many-body potential energy surface and dipole moment surfaces.
abstract: The vibrational spectra of protonated water clusters continue to be of great interest and a significant challenge to theory. We report high-level, coupled-mode anharmonic (VSCF/VCI) calculations of vibrational spectra of two protonated water clusters, H7O3+and H9O4+, using the Watson Hamiltonian and new full-dimensional, high-level many-body potential energy and dipole moment surfaces. These many-body representations are first validated against direct CCSD(T)-F12b/aug-cc-pVTZ calculations of the double-harmonic spectra of these clusters. Then they are used with a 4-mode representation of the potential and 18 coupled modes to obtain the anharmonic coupled-mode spectra of these clusters. The calculated spectra agree well with recent Ar-tagged action spectra. In the case of H9O4+, a "side-by-side" comparison shows a very good agreement with virtually every experimental feature.
authors.affiliation: Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, USA.
authors.forename: Qi
authors.initials: Q
authors.lastname: Yu
authors.affiliation: Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, USA.
authors.forename: Joel M
authors.identifier: 0000000196922672
authors.initials: JM
authors.lastname: Bowman