Investigations of structure and dynamics at phase transitions of various types

Abstract

Phase transitions are very commonly observed in nature and related topics are of much research interest [1–26]. The change of phase in a system takes place due to variation in different thermodynamic variables, like pressure (P ), temperature (T ), magnetic field (h), etc. In addition to being fundamental to the understanding of matter, knowledge of it is important in technological developments. In Fig. 1.1 we show a schematic phase diagram [1] of a normal chemical substance in the P − T plane. The three distinct phases, viz., solid, liquid and gas, in this figure, are separated by different coexistence curves, along each of which two phases coexist with each other in equilibrium. For example, along the red curve, referred to as the fusion curve [1], solid and liquid phases coexist. The gas-solid (pink curve) and gas-liquid (green curve) coexistence curves are referred to as the sublimation and the vaporization curves, respectively [1].