Model for phase coexistence in phase transitions

We propose a general model for describing the phenomena of phase coexistence in relation to pressure induced phase transformations by means of the T-P distribution in statistical thermodynamics. Using the well-known B1-B2 transition in NaCl as a prototype, we demonstrate how phase coexistence gives rise to the changes in the bulk modulus and the equation-of-state across the transition. (C) 2004 Wiley Periodicals, Inc.