A wide-range multiphase equation of state for platinum
В. М. Елькин, V. N. Mikhaylov, A. A. Ovechkin, N. A. Smirnov
Abstract
Abstract The paper presents a semi-empirical wide-range equation of state (EOS) for platinum with account for melting, evaporation, and ionization. The equation is based on a wide spectrum of experimental and calculation data. Parameters for the EOS were adjusted using a genetic algorithm which proved to perform well for optimizations in big data processing. In the regions where no experimental data were available, we used results of first-principles and average-atom model calculations. The EOS was used to calculate the melting curve of platinum to pressures above 1 TPa, sound velocities along the Hugoniot curve, parameters of melting under shock compression, and parameters of the critical point. An improved model is proposed for the shear modulus in ( V , T ) coordinates and its variation along the shock adiabat is calculated.