Anharmonicity of gold under high-pressure and high-temperature

In order to examine the pressure effect on the anharmonicity of Au, EXAFS spectra near Au L3-edge were measured at the temperature range from 300 to 1000 K under pressures up to 14 GPa using large volume high-pressure devices and synchrotron radiation. The values of EXAFS Debye–Waller factors, σ2 and σ3, become smaller with the increase of pressure, which indicates that the potential width become narrower with pressure. The anharmonic effective pair potentials of Au, V(u)=au2/2!+bu3/3!, at 0.1 MPa, 6 and 14 GPa have been calculated. The pressure dependence of the coefficient of thermal expansion has also been evaluated.