Kinetics of Phase Transitions

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].