Eur. Phys. J. B 48, 537-545 (2005)
https://doi.org/10.1140/epjb/e2006-00005-5

Generalized Ehrenfest's approach to phase transitions in multicomponent systems in the presence of an electromagnetic field

¹ Consorzio per lo sviluppo dei Sistemi a Grande Interfase (C.S.G.I.) c/o Dept. Food Technology DISTAAM, Università del Molise, via De Sanctis 86100 Campobasso, Italy
² Dipartimento di Scienze Animali, Vegetali ed Ambientali, Università del Molise, via De Sanctis 86100 Campobasso, Italy

Corresponding author: ^a ambroson@unimol.it

Received: 31 March 2005
Revised: 5 October 2005
Published online: 19 January 2006

Abstract

The path of a transformation is defined and discussed in the framework of classical thermodynamics. The Ehrenfest's approach to the theory of higher order transition is generalized to heterogeneous systems of r components in the presence and in the absence of electromagnetic fields. By introducing a state label the phase transitions, in proximity of singular points, are analysed in terms of the stability theory. Systems, in the presence and in the absence of a magnetic field are discussed in some detail. It is shown that the Ehrenfest approximation about the transition of 2nd order is physically unstable.