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A Gaussian wave packet phase-space representation of quantum canonical statistics

Journal Article · · Journal of Chemical Physics
DOI:https://doi.org/10.1063/1.4927235· OSTI ID:22493441
;  [1]
  1. School of Chemistry, University of Bristol, Bristol BS8 1TS (United Kingdom)
We present a mapping of quantum canonical statistical averages onto a phase-space average over thawed Gaussian wave-packet (GWP) parameters, which is exact for harmonic systems at all temperatures. The mapping invokes an effective potential surface, experienced by the wave packets, and a temperature-dependent phase-space integrand, to correctly transition from the GWP average at low temperature to classical statistics at high temperature. Numerical tests on weakly and strongly anharmonic model systems demonstrate that thermal averages of the system energy and geometric properties are accurate to within 1% of the exact quantum values at all temperatures.
OSTI ID:
22493441
Journal Information:
Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 4 Vol. 143; ISSN JCPSA6; ISSN 0021-9606
Country of Publication:
United States
Language:
English