Thermodynamic properties and phase transitions of γ and liquid uranium: QMD and classical MD modeling

Abstract

The application of molecular dynamics allows us to take into account the influence of temperature on thermodynamic properties and phase transitions. In this work different uranium phases are investigated at finite temperatures by means of quantum and classical molecular dynamics. The stability of high temperature γ phase is discussed. The boundaries of phase stability are estimated based on quantum molecular results. In order to investigate phase transitions new interatomic potential is developed by force-matching method. The melting curve up to 750 GPa is obtained by Z-modified method. The results are in a good agreement with experimental data and classical molecular dynamics simulation by two phase methods up to 100 GPa.The application of molecular dynamics allows us to take into account the influence of temperature on thermodynamic properties and phase transitions. In this work different uranium phases are investigated at finite temperatures by means of quantum and classical molecular dynamics. The stability of high temperature γ phase is discussed. The boundaries of phase stability are estimated based on quantum molecular results. In order to investigate phase transitions new interatomic potential is developed by force-matching method. The melting curve up to 750 GPa is obtained by Z-modified method. The results are in a good agreement with experimental data and classical molecular dynamics simulation by two phase methods up to 100 GPa.