Generalized Brownian dynamics. II. Vibrational relaxation of diatomic molecules in solution

Journal Article · Mon Jan 15 04:00:00 EST 1990 · Journal of Chemical Physics; (USA)

DOI:https://doi.org/10.1063/1.458141· OSTI ID:7185684

Smith, D E; Harris, C B ^[1]

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1. Department of Chemistry, University of California, Berkeley, California 94720 (US) Materials and Chemical Sciences Division, Lawrence Berkeley Laboratory, Berkeley, California 94720 (US)

A simple classical stochastic model for diatomic vibrational relaxation, based on the generalized Langevin equation, is presented. The memory function in the generalized Langevin equation is determined directly from equilibrium force autocorrelation functions for the individual atoms of the diatomic dissolved in the solvent of interest. A simple autoregressive (AR) procedure, developed in a preceding paper (D. E. Smith and C. B. Harris, J. Chem. Phys. {bold 92}, 1304 (1990)), is used for modeling the memory functions to arbitrary order. This model is tested on the system of iodine in Lennard--Jones xenon using fourth order AR approximations for the memory functions, and is found to be very effective in reproducing data from molecular dynamics simulations at two very different densities. Results are discussed in terms of the simplifying assumption that the solvent interaction with the diatomic can be characterized by equilibrium dynamics of single atoms in solution.

• OSTI ID: 7185684
• Journal Information: Journal of Chemical Physics; (USA), Journal Name: Journal of Chemical Physics; (USA) Vol. 92:2; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

657002* -- Theoretical & Mathematical Physics-- Classical & Quantum Mechanics
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BROWNIAN MOVEMENT
COMPUTERIZED SIMULATION
DISPERSIONS
ELEMENTS
ENERGY LEVELS
EQUATIONS
EXCITED STATES
HALOGENS
IODINE
LANGEVIN EQUATION
MIXTURES
NONMETALS
RELAXATION
SIMULATION
SOLUTIONS
STOCHASTIC PROCESSES
STRUCTURE FACTORS
VIBRATIONAL STATES