ABSTRACT
Phase transitions may be classiˆed into several diƒerent types on the basis of the behavior with temperature of the thermodynamic potentials and the order parameter. e order parameter may change discontinuously or continuously at the transition point. In the thermodynamic description of phase transitions, the Helmholtz potential F (constant V) and the Gibbs potential G (constant P) play important roles. A scheme on the basis of the behavior of F or G in the vicinity of the transition point has been developed for the classiˆcation of phase transitions as continuous or discontinuous and is discussed in Section 9.3. Figure 9.1 shows a representative phase diagram in the P-T plane for a single component system.
