Formulation for the melting temperature of alkali halides using the equation of state under varying pressure

This work primarily focuses on predicting the equation of state required to compute the pressure-dependent melting curves of alkali halides. In this work, we propose developing models to describe the melting curve using the Murnaghan, Singh, Kao, Shanker, and Usual-Tait equations of state. Our model explicitly describes the relationships among pressure, bulk modulus, the pressure derivative of bulk modulus, and volume compression. The methodical application of theoretical models to the alkali halides yielded rigorous results that were painstakingly compared with Lindemann’s model to determine the melting temperature. It is shown unambiguously in our work that a significant increase in melting temperature follows from a large increase in bulk modulus and a slight decrease in the rate of the first-order pressure derivative of bulk modulus. This work provides incredible insights into the fundamental mechanisms underlying the influence of pressure on melting temperature. We have verified that our model is unambiguously reliable in extrapolating melting temperature to high pressure.