Novel computational probes of diffusive motion

M. Scott Shell, Pablo G. Debenedetti, Frank H. Stillinger

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

Self-diffusion constants, D, and the atomic-level processes that produce them have been investigated numerically for the binary-mixture Lennard - Jones (BMLJ) model and for liquid silica as described by the Van Beest - Kramer - Van Santen interaction model. The primary conceptual tool for this study is the joint probability distribution for single particles as a function of initial velocity and positional displacement at a given later instant. Self-diffusion constants can be expressed exactly in terms of this probability function. The numerical simulations for the BMLJ case reveal an unusual temperature effect; in contrast to the high-temperature behavior, particles with high initial velocities experience disproportionate retardation in forward displacement. In the silica modeling simulations, diffusive processes have been compared at constant-temperature "isodiffusive" pairs of states, demonstrating a significant role played by the amount of local tetrahedral order that is present in the medium.

Original languageEnglish (US)
Pages (from-to)21329-21333
Number of pages5
JournalJournal of Physical Chemistry B
Volume109
Issue number45
DOIs
StatePublished - Nov 17 2005

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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