Stephen K. Gray
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Stephen K. Gray has a total of 3 co-authors. Here are the top co-authors by number of shared publications:
Evelyn M. Goldfield
Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
4 shared publicationsDmitry M. Medvedev
Chemistry Division, Argonne National Laboratory, Argonne, IL 60439, USA
1 shared publicationLawrence B. Harding
Joint Institute for Laboratory Astrophysics, University of Colorado and National Institute of Standards and Technology, Boulder, Colorado 80309
1 shared publication
Latest Publications
- 1 March 2005
- Published by Elsevier in Computer Physics Communications
- Vol. 166 (2) , 94-108
An OpenMP/MPI approach to the parallelization of iterative four-atom quantum mechanics
- 1 March 2005
- Published by Elsevier in Computer Physics Communications
- Vol. 166 (2) , 94-108
An OpenMP/MPI approach to the parallelization of iterative four-atom quantum mechanics
- 22 July 2002
- Published by AIP Publishing in The Journal of Chemical Physics
- Vol. 117 (4) , 1604-1613
A quantum dynamics study of H2+OH→H2O+H employing the Wu–Schatz–Lendvay–Fang–Harding potential function and a four-atom implementation of the real wave packet method
We carry out numerous six-dimensional wave packet propagations for on theab initio based, Wu–Schatz–Lendvay–Fang–Harding potential energy function. For comparison, some calculations are also carried out on the older but more widely studied potential function of Walch, Dunning, Schatz, and Elgersma. The energy dependence of the total angular momentum cumulative reaction probability is obtained and J-shifting is used to estimate the bimolecular rate constant as a function of temperature. Some calculations are also carried out. A novel J-shifting procedure, designed to more accurately describe the effects of angular momentum, is introduced. We compare our results with transition state theory calculations and experiment. An important feature of our work is the development of an efficient, four-atom, parallel implementation of the real wave packet method, augmented with a recently developed finite difference method.- 22 July 2002
- Published by AIP Publishing in The Journal of Chemical Physics
- Vol. 117 (4) , 1604-1613
A quantum dynamics study of H2+OH→H2O+H employing the Wu–Schatz–Lendvay–Fang–Harding potential function and a four-atom implementation of the real wave packet method
We carry out numerous six-dimensional wave packet propagations for on theab initio based, Wu–Schatz–Lendvay–Fang–Harding potential energy function. For comparison, some calculations are also carried out on the older but more widely studied potential function of Walch, Dunning, Schatz, and Elgersma. The energy dependence of the total angular momentum cumulative reaction probability is obtained and J-shifting is used to estimate the bimolecular rate constant as a function of temperature. Some calculations are also carried out. A novel J-shifting procedure, designed to more accurately describe the effects of angular momentum, is introduced. We compare our results with transition state theory calculations and experiment. An important feature of our work is the development of an efficient, four-atom, parallel implementation of the real wave packet method, augmented with a recently developed finite difference method.- 1 January 1997
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Faraday Transactions
- Vol. 93 (5) , 909-918
Total angular momentum and decay of unimolecular resonances IVR-mediated vibrational predissociation
Full-dimensional wavepacket calculations are carried out on the vibrational predissociation of ArI 2 . With the aid of a parallel computing strategy, we consider systems with total angular momentum quantum numbers up to J=24. Previous work for low J has shown that fragmentation occurs via a sparse limit intramolecular vibrational energy redistribution mechanism involving passage through a few intermediate dark states. Despite many more states becoming available as J is increased, this mechanism continues to dominate. Inspection of wavepacket densities and characterization of the dark states helps explain why the mechanism persists with increasing J.
- 1 January 1997
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Faraday Transactions
- Vol. 93 (5) , 909-918
Total angular momentum and decay of unimolecular resonances IVR-mediated vibrational predissociation
Full-dimensional wavepacket calculations are carried out on the vibrational predissociation of ArI 2 . With the aid of a parallel computing strategy, we consider systems with total angular momentum quantum numbers up to J=24. Previous work for low J has shown that fragmentation occurs via a sparse limit intramolecular vibrational energy redistribution mechanism involving passage through a few intermediate dark states. Despite many more states becoming available as J is increased, this mechanism continues to dominate. Inspection of wavepacket densities and characterization of the dark states helps explain why the mechanism persists with increasing J.
- 15 October 1993
- Published by AIP Publishing in The Journal of Chemical Physics
- Vol. 99 (8) , 5812-5827
Quantum dynamics of Renner–Teller vibronic coupling: The predissociation of HCO
A Hamiltonian model and parity-adapted wave packet representation are developed to describe a rotating triatomic system with two Renner–Teller coupled potential surfaces, and HCO predissociation is studied. New configuration interaction calculations on HCO are performed to determine its excited Ã(2A″) potential surface, and Bowman, Bittman, and Harding’s X̃(2A′) ground potential surface is employed. The properties of many resonances, correlating with stretch/bend excitations on the A″ surface, are determined. Resonance energies and decay constants are in good agreement with experimental results of Houston and co-workers, but CO rotational product distributions tend to be hotter and narrower than experiment, particularly for pure bend excitations. Wave packet dynamics involves growth of amplitude on the A′ surface near collinear geometries via Renner–Teller coupling, and subsequent adiabatic evolution to determine product distributions. The wave packets probe a previously untested part of the A′ surface, and point to the need for improvements of this surface.
- 15 October 1993
- Published by AIP Publishing in The Journal of Chemical Physics
- Vol. 99 (8) , 5812-5827
Quantum dynamics of Renner–Teller vibronic coupling: The predissociation of HCO
A Hamiltonian model and parity-adapted wave packet representation are developed to describe a rotating triatomic system with two Renner–Teller coupled potential surfaces, and HCO predissociation is studied. New configuration interaction calculations on HCO are performed to determine its excited Ã(2A″) potential surface, and Bowman, Bittman, and Harding’s X̃(2A′) ground potential surface is employed. The properties of many resonances, correlating with stretch/bend excitations on the A″ surface, are determined. Resonance energies and decay constants are in good agreement with experimental results of Houston and co-workers, but CO rotational product distributions tend to be hotter and narrower than experiment, particularly for pure bend excitations. Wave packet dynamics involves growth of amplitude on the A′ surface near collinear geometries via Renner–Teller coupling, and subsequent adiabatic evolution to determine product distributions. The wave packets probe a previously untested part of the A′ surface, and point to the need for improvements of this surface.