Interference and quantization in semiclassical response functions

Journal Article · Fri Mar 28 04:00:00 EDT 2008 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.2841943· OSTI ID:21104009

Gruenbaum, Scott M; Loring, Roger F ^[1]

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1. Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853 (United States)

Application of the Herman-Kluk semiclassical propagator to the calculation of spectroscopic response functions for anharmonic oscillators has demonstrated the quantitative accuracy of these approximate dynamics. In this approach, spectroscopic response functions are expressed as multiple phase-space integrals over pairs of classical trajectories and their associated stability matrices. Here we analyze the Herman-Kluk semiclassical approximation to a linear response function and determine the origin of the capacity of this method to reproduce quantum effects in a response function from classical dynamical information. Our analysis identifies those classical trajectories that contribute most significantly to the response function on different time scales. This finding motivates a procedure for computing the linear response function in which the interference between pairs of classical trajectories is treated approximately, resulting in an integral over a single average trajectory, as in a purely classical calculation.

• OSTI ID: 21104009
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 12 Vol. 128; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANHARMONIC OSCILLATORS
INTEGRALS
INTERFERENCE
PHASE SPACE
PROPAGATOR
QUANTIZATION
RESPONSE FUNCTIONS
SEMICLASSICAL APPROXIMATION
TRAJECTORIES