dorsal/arxiv
View SchemaQuasi-chemical Theory for the Statistical Thermodynamics of the Hard Sphere Fluid
| Authors | Lawrence R. Pratt, Randall A. LaViolette, Maria A. Gomez, Mary E. Gentile |
|---|---|
| Categories | |
| ArXiv ID | physics/0104025 |
| URL | https://arxiv.org/abs/physics/0104025 |
Abstract
We develop a quasi-chemical theory for the study of packing thermodynamics in dense liquids. The situation of hard-core interactions is addressed by considering the binding of solvent molecules to a precisely defined `cavity' in order to assess the probability that the `cavity' is entirely evacuated. The primitive quasi-chemical approximation corresponds to a extension of the Poisson distribution used as a default model in an information theory approach. This primitive quasi-chemical theory is in good qualitative agreement with the observations for the hard sphere fluid of occupancy distributions that are central to quasi-chemical theories but begins to be quantitatively erroneous for the equation of state in the dense liquid regime of $\rho d^3>$0.6. How the quasi-chemical approach can be iterated to treat correlation effects is addressed. Consideration of neglected correlation effects leads to a simple model for the form of those contributions neglected by the primitive quasi-chemical approximation. These considerations, supported by simulation observations, identify a `break away' phenomena that requires special thermodynamic consideration for the zero (0) occupancy case as distinct from the rest of the distribution. A empirical treatment leads to a one parameter model occupancy distribution that accurately fits the hard sphere equation of state and observed distributions.
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"abstract": "We develop a quasi-chemical theory for the study of packing thermodynamics in\ndense liquids. The situation of hard-core interactions is addressed by\nconsidering the binding of solvent molecules to a precisely defined `cavity\u0027 in\norder to assess the probability that the `cavity\u0027 is entirely evacuated. The\nprimitive quasi-chemical approximation corresponds to a extension of the\nPoisson distribution used as a default model in an information theory approach.\nThis primitive quasi-chemical theory is in good qualitative agreement with the\nobservations for the hard sphere fluid of occupancy distributions that are\ncentral to quasi-chemical theories but begins to be quantitatively erroneous\nfor the equation of state in the dense liquid regime of $\\rho d^3\u003e$0.6. How the\nquasi-chemical approach can be iterated to treat correlation effects is\naddressed. Consideration of neglected correlation effects leads to a simple\nmodel for the form of those contributions neglected by the primitive\nquasi-chemical approximation. These considerations, supported by simulation\nobservations, identify a `break away\u0027 phenomena that requires special\nthermodynamic consideration for the zero (0) occupancy case as distinct from\nthe rest of the distribution. A empirical treatment leads to a one parameter\nmodel occupancy distribution that accurately fits the hard sphere equation of\nstate and observed distributions.",
"arxiv_id": "physics/0104025",
"authors": [
"Lawrence R. Pratt",
"Randall A. LaViolette",
"Maria A. Gomez",
"Mary E. Gentile"
],
"categories": [
"physics.chem-ph"
],
"title": "Quasi-chemical Theory for the Statistical Thermodynamics of the Hard Sphere Fluid",
"url": "https://arxiv.org/abs/physics/0104025"
},
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