The effects of a dynamic lattice on methane self-diffusivity calculations in AlPO4-5

Kendall T. Thomson, Alon V. McCormick, H. Ted Davis

Research output: Contribution to journalArticle

18 Scopus citations

Abstract

Canonical ensemble molecular dynamics simulations were conducted for methane diffusion in AlPO4-5 in order to assess the role of the lattice motion on adsorbate diffusivity in straight pore zeolites. Both a static lattice model and a full dynamic lattice model were used at a loading of 1.5 methane/unit cell at 295 K. Although recent simulation work has asserted that there should be a difference, we show that there is little difference in the observed methane diffusivity (1.26 × 10-7 m2/s) and passing frequency (0.305) when a static lattice approximation is used over a full dynamic lattice (1.33 × 10-7 m2/s and 0.328). Furthermore, we introduce a methodology for handling lattice motion in molecular simulations by utilizing the normal vibrational modes in a harmonic crystal approximation.

Original languageEnglish (US)
Pages (from-to)3345-3350
Number of pages6
JournalJournal of Chemical Physics
Volume112
Issue number7
DOIs
StatePublished - Feb 15 2000

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