Molecular dynamics study of methane and xenon in silicalite

Journal Article · Thu Oct 18 00:00:00 EDT 1990 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100384a047· OSTI ID:6047039

June, R L; Bell, A T; Theodorou, D N ^[1]

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1. Univ. of California, Berkeley (USA)

The dynamic and equilibrium properties of two different sorbate molecules, xenon and methane, in the pentasil zeolite silicalite were studied with molecular dynamics simulations. A rigid polyatomic model was employed for methane, while xenon was represented as a Lennard-Jones sphere. The zeolite lattice was assumed rigid. The effect of intracrystalline occupancy and temperature on the structure and dynamics of the sorbed phase was investigated. Predicted self-diffusivities are in good agreement with NMR measurements. Except at the lowest temperature studied, 200 K, the sorbate self-diffusivities were found to decrease monotonically with occupancy. At 200 K, the self-diffusivities exhibit a weak maximum before decreasing at high loadings. This maximum is attributed to the trapping of sorbate molecules in small potential wells formed within the pore network of the zeolite at low occupancy. The single particle density distribution function, {rho}{sup 1}(r), shows that at low loadings sorbate molecules are localized preferentially in the sinusoidal channels and avoid the energetically less favorable channel intersections and straight channels. At higher loadings, partial order is observed in the intracrystalline fluid.

• OSTI ID: 6047039
• Journal Information: Journal of Physical Chemistry; (USA), Vol. 94:21; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
09 BIOMASS FUELS
ZEOLITES
SORPTIVE PROPERTIES
THERMODYNAMIC PROPERTIES
DISTRIBUTION FUNCTIONS
LATTICE PARAMETERS
METHANE
MOLECULAR MODELS
PHASE STUDIES
SILICA
XENON
ALKANES
CHALCOGENIDES
ELEMENTS
FLUIDS
FUNCTIONS
GASES
HYDROCARBONS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
MATERIALS
MATHEMATICAL MODELS
MINERALS
NONMETALS
ORGANIC COMPOUNDS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RARE GASES
SILICON COMPOUNDS
SILICON OXIDES
SURFACE PROPERTIES
360602* - Other Materials- Structure & Phase Studies
360603 - Materials- Properties
091000 - Biomass Fuels- Properties & Composition- (1990-)