Application of a new ensemble conserving quantum dynamics simulation algorithm to liquid para-hydrogen and ortho-deuterium

Journal Article · Sun Jun 28 04:00:00 EDT 2015 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4922888· OSTI ID:22490832

Smith, Kyle K. G., ^[1]; Nyman, Gunnar ^[2]; Cunsolo, Alessandro ^[3]

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1. Institute for Computational Engineering and Sciences and Department of Chemistry,University of Texas at Austin, Austin, Texas 78712 (United States)
2. Physical Chemistry, Department of Chemistry and Molecular Biology, University of Gothenburg, SE 41296 Gothenburg (Sweden)
3. Photon Sciences Directorate, Brookhaven National Laboratory, P.O. Box 5000, Upton, New York 11973 (United States)

We apply the Feynman-Kleinert Quasi-Classical Wigner (FK-QCW) method developed in our previous work [Smith et al., J. Chem. Phys. 142, 244112 (2015)] for the determination of the dynamic structure factor of liquid para-hydrogen and ortho-deuterium at state points of (T = 20.0 K, n = 21.24 nm{sup −3}) and (T = 23.0 K, n = 24.61 nm{sup −3}), respectively. When applied to this challenging system, it is shown that this new FK-QCW method consistently reproduces the experimental dynamic structure factor reported by Smith et al. [J. Chem. Phys. 140, 034501 (2014)] for all momentum transfers considered. This shows that FK-QCW provides a substantial improvement over the Feynman-Kleinert linearized path-integral method, in which purely classical dynamics are used. Furthermore, for small momentum transfers, it is shown that FK-QCW provides nearly the same results as ring-polymer molecular dynamics (RPMD), thus suggesting that FK-QCW provides a potentially more appealing algorithm than RPMD since it is not formally limited to correlation functions involving linear operators.

• OSTI ID: 22490832
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 24 Vol. 142; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ALGORITHMS
DEUTERIUM
HYDROGEN
LIQUIDS
MOLECULAR DYNAMICS METHOD
MOMENTUM TRANSFER
PATH INTEGRALS
POLYMERS
SIMULATION
STRUCTURE FACTORS