Homo- and heterocoordination in nonadditive hard-sphere mixtures and a test of the van der Waals one-fluid model

Journal Article · Sat Jan 01 00:00:00 EST 1994 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.466967· OSTI ID:5428417

Jung, J; Jhon, M ^[1]; Ree, F H ^[2]

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1. Department of Chemistry, Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)
2. University of California, Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

An equimolar mixture of hard spheres with equal diameter [ital d], having an unequal collision diameter [ital d][sub 12] between unlike species, favors a hetercoordinated arrangement if [ital d][sub 12] lies between 0.65[ital d] and [ital d], and a homocoordinated packing below [ital d][sub 12]=0.65[ital d]. At [ital d][sub 12][lt]0.65[ital d], hard spheres of one type move increasingly unaffected by the presence of hard spheres of the other type. This conclusion was drawn from Monte Carlo (MC) simulations over large ranges of density and [ital d][sub 12] and originates in the fact that collisions between like-species at [ital d] prevent collisions of unlike-species at shorter distance [ital d][sub 12][lt][ital d]. The observed shift of hetero- to homocoordination affects equation-of-state data as well. Additionally, a test of the van der Waals one-fluid model of mixtures by the Monte Carlo data shows that this model significantly overestimates the pressure at high density, and hence, is less suitable for nonadditive hard sphere mixtures. As expected, the MC data suggest a fluid phase separation at [ital d][sub 12][gt][ital d].

• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5428417
• Journal Information: Journal of Chemical Physics; (United States), Vol. 100:1; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BINARY MIXTURES
SIMULATION
DENSITY
EQUATIONS OF STATE
HARD-SPHERE MODEL
MONTE CARLO METHOD
VAN DER WAALS FORCES
CALCULATION METHODS
DISPERSIONS
EQUATIONS
MIXTURES
PHYSICAL PROPERTIES
665000* - Physics of Condensed Matter- (1992-)
661300 - Other Aspects of Physical Science- (1992-)