Data di Pubblicazione:
2007
Citazione:
Smooth cut-off HRT equations / C.D. Ionescu, L. Reatto, D. Pini, A. Parola. ((Intervento presentato al convegno Workshop on new directions in liquid state theory tenutosi a Lyon, France nel 2007.
Abstract:
We provide a comprehensive presentation of the Hierarchical Reference Theory (HRT) in the
smooth cut-off formulation. A simple and self-consistent derivation of the hierarchy of differential
equations is supplemented by a comparison with the known sharp cut-off HRT. Then, the theory is
applied to a hard core Yukawa fluid (HCYF): a closure, based on a mean spherical approximation
ansatz, is studied in detail and its intriguing relationship to the self consistent Ornstein-Zernike
approximation is discussed. The asymptotic properties, close to the critical point are investigated
and compared to the renormalization group results both above and below the critical temperature.
The HRT free energy is always a convex function of the density, leading to flat isotherms in the twophase
region with a finite compressibility at coexistence. This makes HRT the sole liquid-state theory
able to obtain directly fluid-fluid phase equilibrium without resorting to the Maxwell construction.
The way the mean field free energy is modified due to the inclusion of density fluctuations suggests
how to identify the spinodal curve. Thermodynamic properties and correlation functions of the
HCYF are investigated for three values of the inverse Yukawa range: z = 1.8, z = 4 and z = 7
where Monte Carlo simulations are available. The stability of the liquid-vapor critical point with
respect to freezing is also studied.
Tipologia IRIS:
14 - Intervento a convegno non pubblicato
Elenco autori:
C.D. Ionescu, L. Reatto, D. Pini, A. Parola
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