ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
We review experimental results for the locus in the temperature–density plane of isothermal Cv (constant volume heat capacity) extrema of Ar, Kr and Xe, and published Percus–Yevick and simulation equations of state. It is likely that the locus of Cv maxima terminates at the critical point. We report new long (960 million Monte Carlo steps), 864 particle simulations of the heat capacity for the truncated Lennard-Jones potential (cutoff=2.5σ) near the liquid coexistence line, and establish directly that the locus of Cv minima intersects the coexistence line. On the basis of calculations and simulations for model systems, we induce that previously reported Cv extrema are caused by the interplay of three physical effects that we term, "aggregation," "caging," and "soft-core penetration." We test our hypothesis by carrying out calculations for a one-dimensional, nearest-neighbor, infinite-chain, truncated interaction model with the following potentials: Lennard-Jones, Lennard-Jones with hard core, Lennard-Jones with hard core and no soft repulsion, square well, and the inverse twelfth. Using our physical understanding, we successfully explain the qualitative changes in the behavior of the Cv extrema as the interaction potential changes.© 1997 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.474068
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