Fully coupled six-dimensional calculations of the water dimer vibration-rotation-tunneling states with a split Wigner pseudo spectral approach

Title:
Fully coupled six-dimensional calculations of the water dimer vibration-rotation-tunneling states with a split Wigner pseudo spectral approach
Authors:
Leforestier, Claude; Braly, Linda B.; Liu, Kun; Elrod, Matthew J.; Saykally, Richard J.
Abstract:
A novel and efficient pseudospectral method for performing fully coupled six-dimensional bound state dynamics calculations is presented, including overall rotational effects. A Lanczos based iterative diagonalization scheme produces the energy levels in increasing energies. This scheme, which requires repetitively acting the Hamiltonian operator on a vector, circumvents the problem of constructing the full matrix. This permits the use of ultralarge molecular basis sets (up to over one million states for a given symmetry) in order to fully converge the calculations. The Lanczos scheme was conducted in a symmetry adapted spectral representation, containing Wigner functions attached to each monomer. The Hamiltonian operator has been split into different terms, each corresponding to an associated diagonal or nearly diagonal representation. The potential term is evaluated by a pseudospectral scheme of Gaussian accuracy, which guarantees the variational principle. Spectroscopic properties are computed with this method for four of the most widely used water dimer potentials, and compared against recent terahertz laser spectroscopy results. Comparisons are also made with results from other dynamics methods, including quantum Monte Carlo (QMC) and reversed adiabatic approximation calculations. None of the potential surfaces produces an acceptable agreement with experiments. While QMC methods yield good results for ground (nodeless) states, they are highly inaccurate for excited states.
Citation:
Leforestier, C., L.B. Braly, K. Liu, M.J. Elrod, and R.J. Saykally. 1997. "Fully Coupled Six-Dimensional Calculations of the Water Dimer Vibration-Rotation-Tunneling States with a Split Wigner Pseudo Spectral Approach." Journal of Chemical Physics 106: 8527.
Publisher:
American Institute of Physics
DATE ISSUED:
1997-5-22
Department:
Chemistry
Type:
article
PUBLISHED VERSION:
10.1063/1.473908
PERMANENT LINK:
http://hdl.handle.net/11282/309800

Full metadata record

DC FieldValue Language
dc.contributor.authorLeforestier, Claudeen_US
dc.contributor.authorBraly, Linda B.en_US
dc.contributor.authorLiu, Kunen_US
dc.contributor.authorElrod, Matthew J.en_US
dc.contributor.authorSaykally, Richard J.en_US
dc.date.accessioned2013-12-23T16:18:10Zen
dc.date.available2013-12-23T16:18:10Zen
dc.date.issued1997-5-22en
dc.identifier.citationLeforestier, C., L.B. Braly, K. Liu, M.J. Elrod, and R.J. Saykally. 1997. "Fully Coupled Six-Dimensional Calculations of the Water Dimer Vibration-Rotation-Tunneling States with a Split Wigner Pseudo Spectral Approach." Journal of Chemical Physics 106: 8527.en_US
dc.identifier.issn0021-9606en_US
dc.identifier.urihttp://hdl.handle.net/11282/309800en
dc.description.abstractA novel and efficient pseudospectral method for performing fully coupled six-dimensional bound state dynamics calculations is presented, including overall rotational effects. A Lanczos based iterative diagonalization scheme produces the energy levels in increasing energies. This scheme, which requires repetitively acting the Hamiltonian operator on a vector, circumvents the problem of constructing the full matrix. This permits the use of ultralarge molecular basis sets (up to over one million states for a given symmetry) in order to fully converge the calculations. The Lanczos scheme was conducted in a symmetry adapted spectral representation, containing Wigner functions attached to each monomer. The Hamiltonian operator has been split into different terms, each corresponding to an associated diagonal or nearly diagonal representation. The potential term is evaluated by a pseudospectral scheme of Gaussian accuracy, which guarantees the variational principle. Spectroscopic properties are computed with this method for four of the most widely used water dimer potentials, and compared against recent terahertz laser spectroscopy results. Comparisons are also made with results from other dynamics methods, including quantum Monte Carlo (QMC) and reversed adiabatic approximation calculations. None of the potential surfaces produces an acceptable agreement with experiments. While QMC methods yield good results for ground (nodeless) states, they are highly inaccurate for excited states.en_US
dc.language.isoen_USen_US
dc.publisherAmerican Institute of Physicsen_US
dc.identifier.doi10.1063/1.473908en
dc.subject.departmentChemistryen_US
dc.titleFully coupled six-dimensional calculations of the water dimer vibration-rotation-tunneling states with a split Wigner pseudo spectral approachen_US
dc.typearticleen_US
dc.identifier.journalJournal of Chemical Physicsen_US
dc.subject.keywordWateren_US
dc.subject.keywordQuasimoleculesen_US
dc.subject.keywordRotational-vibrational statesen_US
dc.subject.keywordTunnelingen_US
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