Document Type

Article

Subject Area(s)

Chemical Physics

Abstract

We present a time-dependent semiclassical method based on quantum trajectories. Quantum-mechanical effects are described via the quantum potential computed from the wave function density approximated as a linear combination of Gaussian fitting functions. The number of the fitting functions determines the accuracy of the approximate quantum potential (AQP). One Gaussian fit reproduces time-evolution of a Gaussian wave packet in a parabolic potential. The limit of the large number of fitting Gaussians and trajectories gives the full quantum-mechanical result. The method is systematically improvable from classical to fully quantum. The fitting procedure is implemented as a gradient minimization. We also compare AQP method to the widely used semiclassical propagator of Herman and Kluk by computing energy-resolved transmission probabilities for the Eckart barrier from the wave packet time-correlation functions. We find the results obtained with the Herman–Kluk propagator to be essentially equivalent to those of AQP method with a one-Gaussian density fit for several barrier widths.

Rights

Copyright 2003 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.

The following article appeared in

Garashchuk, S. & Rassolov, V. A. (2003). Semiclassical dynamics with quantum trajectories: Formulation and comparison with the semiclassical initial value representation propagator. The Journal of Chemical Physics, 118, 2482. http://dx.doi.org/10.1063/1.1535421

and may be found at

http://scitation.aip.org/content/aip/journal/jcp/118/6/10.1063/1.1535421

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