ABSTRACT
Many systems exist in multiple phases, depending on the values of external parameters, for example, temperature (T ), pressure (P), and so on. In this context, consider a fluid (e.g., water), which can exist in three phases, viz., liquid, solid, and gas. The phase diagram of this fluid in the (T ,P)-plane is shown in Figure 1.1. The chosen phase at a particular (T ,P)-value is the one with lowest Gibbs potentialG(T ,P). This phase diagram is characterized by a range of fascinating features, for example, lines of first-order phase transitions, a second-order critical point, a triple point, and so on. The correct understanding of these features is of great scientific and technological importance. We have gained a thorough understanding of the equilibrium aspects of phase transitions (and phase diagrams) through many important works, starting with the seminal contribution of Van der Waals [1,2].
