Generalized Brownian dynamics. I. Numerical integration of the generalized Langevin equation through autoregressive modeling of the memory function

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

DOI:https://doi.org/10.1063/1.458140· OSTI ID:7021213

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

A method is presented for numerical integration of the generalized Langevin equation (GLE) based on modeling of the random force'' as a discrete autoregressive process. This modeling procedure, drawn from digital signal processing and spectral estimation methods which have been used extensively in electrical engineering applications, provides for efficient evaluation of the friction integral in the GLE as well as for generation of a random force process with the desired spectrum. The method is shown, through comparison with molecular dynamics results, to be effective in simulating the force autocorrelation function of an iodine atom dissolved in Lennard-Jones (LJ) xenon. In a companion paper this method is applied in a simulation of the vibrational relaxation of I{sub 2} in LJ xenon at two very different densities and found to perform well.

• OSTI ID: 7021213
• Journal Information: Journal of Chemical Physics; (USA), Vol. 92:2; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
IODINE
DISSOLUTION
SOLUTIONS
STRUCTURE FACTORS
XENON
SOLVENT PROPERTIES
BROWNIAN MOVEMENT
COMPUTERIZED SIMULATION
CORRELATION FUNCTIONS
LANGEVIN EQUATION
SOLUTES
SOLVENTS
DISPERSIONS
ELEMENTS
EQUATIONS
FLUIDS
FUNCTIONS
GASES
HALOGENS
MIXTURES
NONMETALS
RARE GASES
SIMULATION
657002* - Theoretical & Mathematical Physics- Classical & Quantum Mechanics