The analysis on high pressure melting temperature dependence of the thermodynamic parameters of solids

Based on the relation between thermodynamic properties and temperature, one simple model has been developed to predict the melting of solids under high pressures. For this model, a critical temperature representing the melting temperature is defined, compared to the reference temperature (300 K). At any given pressure, both the reference volume (300 K) and the critical volume (at the melting temperature) are obtained. Then, upon the relation of thermal pressure and temperature, the melting temperatures of solids at high-pressures can be easily calculated. Three types of solids including halide (LiF), oxide (FeO) and silicate (CaMgSi2O6) have been employed to test the reliability of the model. The obtained results indicate that the model is reliable due to a good agreement between the calculated results and the existing experimental melting data for lithium fluoride (LiF), diopside (CaMgSi2O6) and wustite (FeO). Also, it has been better demonstrated that our model is a much better and more precise method in estimating the melting of solids at extreme pressure than the empirical melting equations. (C) 2001 Elsevier Science B.V. All rights reserved.