A. Amadei et al., ON THE USE OF THE QUASI-GAUSSIAN ENTROPY THEORY IN NONCANONICAL ENSEMBLES - I - PREDICTION OF TEMPERATURE-DEPENDENCE OF THERMODYNAMIC PROPERTIES, The Journal of chemical physics, 109(8), 1998, pp. 3004-3016
In previous articles we derived and tested the quasi-Gaussian entropy
theory, a description of the excess Helmholtz free energy in terms of
the potential energy distribution, instead of the configurational part
ition function. We obtained in this way the temperature dependence of
thermodynamic functions in the canonical ensemble assuming a Gaussian,
Gamma or Inverse Gaussian distribution. In this article we extend the
theory to describe the temperature dependence of thermodynamic proper
ties in an exact way in the isothermal-isobaric and grand canonical en
semble, using the distribution of the appropriate heat function. For b
oth ensembles restrictions on and implications of these distributions
are discussed, and the thermodynamics assuming a Gaussian or (divergin
g) Gamma distribution is derived.: These cases have been tested for wa
ter at constant pressure, and the results for the latter case are sati
sfactory. Also the distribution of the heat function of some theoretic
al model systems is considered. (C) 1998 American Institute of Physics
. [S0021-9606(98)50232-2].