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

Journal Article · Tue Jul 28 00:00:00 EDT 2015 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4927235· OSTI ID:22493441

Coughtrie, David J.; Tew, David P. ^[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, Vol. 143, Issue 4; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
GAUSS FUNCTION
MAPPING
PHASE SPACE
POTENTIALS
QUANTUM MECHANICS
STATISTICS
SURFACES
TEMPERATURE DEPENDENCE
WAVE PACKETS