Vibrational relaxation in simple fluids

Comparison of theory and simulation

Mark Tuckerman, B. J. Berne

Research output: Contribution to journalArticle

Abstract

General theoretical expressions for the dephasing and energy relaxation times of a stiff oscillator in simple fluids are derived from the GLE and a critical discussion of the dynamic processes in these systems is given. In addition new methodological aspects of stochastic and full molecular dynamics simulations are discussed. The new reversible integrator based on the Trotter factorization of the classical propagator is used to directly simulate the vibrational energy and phase relaxation of a stiff classical oscillator dissolved in a Lennard-Jones bath. We compare the "real" relaxation from full MD simulations with that predicted by Kubo theory and by the generalized Langevin equation (GLE) with memory friction determined from the full molecular dynamics. It is found that the GLE gives very good agreement with MD for the vibrational energy relaxation, even for nonlinear oscillators far from equilibrium. The dephasing relaxation is also well approximated by the GLE.

Original languageEnglish (US)
Pages (from-to)7301-7318
Number of pages18
JournalThe Journal of chemical physics
Volume98
Issue number9
StatePublished - 1993

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molecular relaxation
Molecular dynamics
Fluids
fluids
oscillators
Factorization
Relaxation time
simulation
Friction
molecular dynamics
Data storage equipment
integrators
Computer simulation
factorization
energy
baths
friction
relaxation time
propagation

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

Vibrational relaxation in simple fluids : Comparison of theory and simulation. / Tuckerman, Mark; Berne, B. J.

In: The Journal of chemical physics, Vol. 98, No. 9, 1993, p. 7301-7318.

Research output: Contribution to journalArticle

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