Theoretical approach to predict the phase transition of NaH under pressure

Frontiers of Physics and Plasma Science

Jain, Aayushi^1 ; Dixit, R.C.^1

Department of Physics, Government Holkar Science College, A. B. Road, Indore MP

452017, India^1

关键词: Coordination number;    High-pressure behavior;    Interionic interactions;    Repulsive interactions;    Structural phase transition;    Theoretical approach;    Transition pressure;    Van der Waals interaction;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/836/1/012035/pdf
DOI  :  10.1088/1742-6596/836/1/012035

来源: IOP

【 摘 要 】

This paper is dealing with the high pressure behavior of alkali halide (NaH) and a structural phase transition from NaCl to CsCl phase is predicted under high pressure. We have adopted an effective interionic interaction potential, which includes the long range Coulomb, van der Waals (vdW) interaction and the short-range repulsive interaction upto second-neighbor ions within the Hafemeister and Flygare approach. The thermodynamic requirement, for the equality of free energies, at a phase boundary, suggests that the transition pressure of NaH occur at 37 GPa. The transition involves the coordination number increasing from 6 for the NaCl-type structure to 8 for the CsCl-type structure.