| Autor: |
Amadei, A., Apol, M. E. F., Brancato, G., Di Nola, A. |
| Předmět: |
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| Zdroj: |
Journal of Chemical Physics; 3/15/2002, Vol. 116 Issue 11, p4437, 13p, 3 Charts, 13 Graphs |
| Abstrakt: |
The quasi-Gaussian entropy (QGE) theory employs the fact that a free-energy change can be written as the moment-generating function of the appropriate probability distribution function of macroscopic fluctuations of an extensive property. By modeling this distribution, one obtains a model of free energy and resulting thermodynamics as a function of one state variable. In this paper the QGE theory has been extended towards theoretical models or equations of state (EOS’s) of the thermodynamics of semiclassical systems as a function of two state variables. Two “monovariate” QGE models are combined in the canonical ensemble: one based on fluctuations of the excess energy (the confined gamma state giving the temperature dependence) and the other based on fluctuations of the reduced electromagnetic moment [various models as derived in the preceding paper [Apol, Amadei, and Di Nola, J. Chem. Phys. 116, 4426 (2002)], giving the external field dependence]. This provides theoretical EOS’s for fluid systems as a function of both temperature and electromagnetic field. Special limits of these EOS’s are considered: the general weak-field EOS and the limit to a Curie’s law behavior. Based on experimental data of water and simulation data using the extended simple point charge (SPC/E) water model at 45.0 and 55.51 mol/dm3, the specific EOS based on a relatively simple combination of the confined gamma state model with a discrete uniform state field model accurately reproduces the dielectric properties of water at constant density, as the temperature dependence of the weak-field dielectric constant for gases and liquids, and the field dependence of the dielectric constant of liquids. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR] |
| Databáze: |
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