Adiabats (∂T/∂P)s and Grüneisen parameter of NaCl up to 50 kilobars and 800°C

Abstract

The adiabatic pressure derivative of temperature (∂T/∂P)s of sodium chloride has been measured by adiabatic compression up to 50 kbars and 800°C using an end‐loaded piston cylinder apparatus with solid pressure medium. Our measurements at room temperature are in very good agreement with measurements using hydrostatic fluid cells (Boehler et al., 1977). The results can be represented by a power law relationship between (∂T/∂P)s and volume of the form (∂T/∂P)s,P = (∂T/∂P)s,P=0 (V/V0)n. We estimate powers n of 6.3 and 5.3 at room temperature and 800°C, respectively. The Grüneisen parameter γ can be calculated from the thermodynamic equation γ = Ks/T = (∂T/∂P)s, where Ks is the adiabatic bulk modulus; γ is found to be independent of temperature within our pressure and temperature range.