Ruby, metals, andMgOas alternative pressure scales: A semiempirical description of shock-wave, ultrasonic, x-ray, and thermochemical data at high temperatures and pressures

Abstract

perature range from 10– 20 K up to the melting temperature and to compression x = V / V0 = 0.5– 0.7. The comparison of the calculated room-temperature isotherms for these metals with quasihydrostatic measurements supports recently proposed ruby pressure scales. We recommend a new ruby pressure scale in the form P = A /0 1+ m /0 with parameters A = 1884 GPa and m = 5.5. The cross check on independent data confirms the obtained PVT equations of state of Ag, Al, Au, Cu, Pt, Ta, W, MgO, and diamond. The equations of state of these materials obtained here provide accurate and versatile means for calibrating pressure at all temperatures below the melting point. Furthermore, they can be used for accurate tabulation of thermodynamic properties heat capacities, entropies of these reference substances in a wide P-T range.