Centroid-density quantum rate theory: Dynamical treatment of classical recrossing

Journal Article · Sun Aug 01 00:00:00 EDT 1993 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.465284· OSTI ID:6487151

Schenter, G K; Messina, M; Garrett, B C ^[1]

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1. Molecular Science Research Center, Pacific Northwest Laboratory, Richland, Washington 99352 (United States)

A new method is presented for the calculation of quantum mechanical rate constants for activated processes. This method is a hybrid approach involving Feynman path integrals and classical dynamics that is an extension of previous work of Messina, Schenter, and Garrett [J. Chem. Phys. [bold 98], 8525 (1993)]. We make an ansatz for the quantum mechanical analog to the classical flux correlation function expression for the rate constant. This expression involves an imaginary-time, phase-space Feynman path integral, with the dividing surface and characteristic function expressed as a function of the phase-space centroid variables. The reactive flux correlation function is obtained from a classical-like expression in which the characteristic function is evaluated by evolving the phase-space centroid variables as if they were [ital classical] [ital dynamical] [ital variables]. We show that the theory gives exact analytic results in the high temperature and harmonic limits. The theory is further tested on a model anharmonic two-dimensional system of an Eckart barrier coupled to a harmonic oscillator. The results of the theory compare favorably to accurate numerical calculations.

• DOE Contract Number: AC06-76RL01830
• OSTI ID: 6487151
• Journal Information: Journal of Chemical Physics; (United States), Vol. 99:3; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CHEMICAL REACTIONS
CALCULATION METHODS
ACCURACY
ACTIVATION ENERGY
CLASSICAL MECHANICS
CORRELATION FUNCTIONS
COUPLING
FEYNMAN PATH INTEGRAL
HARMONIC OSCILLATORS
HARMONIC POTENTIAL
NUMERICAL DATA
PHASE SPACE
QUANTUM MECHANICS
TEMPERATURE RANGE
TWO-DIMENSIONAL CALCULATIONS
DATA
ELECTRONIC EQUIPMENT
ENERGY
EQUIPMENT
FUNCTIONS
INFORMATION
INTEGRALS
MATHEMATICAL SPACE
MECHANICS
NUCLEAR POTENTIAL
OSCILLATORS
POTENTIALS
SPACE
400201* - Chemical & Physicochemical Properties