Global equation of state for copper

Abstract

A new, tabular (SESAME format) equation of state for Cu, suitable for use in hydrodynamic simulations, is described and compared to experimental data. Pressures, internal energies, and Helmholtz free energies are tabulated as functions of temperature and density. The new equation of state builds on the theoretical investigations of Greeff, et al., (J. Phys. Chem. Solids 67, 2033 (2006)), but extends the range of densities and temperatures covered to 10 -5-10 5 g/cc and 0-10 8K. The staticlattice cold curve is modeled using the semi-empirical stabilized jellium equation near ambient densities, LDA and GGA density-functional predictions at moderate compressions, and Thomas- Fermi-Dirac theory at high compressions. The Johnson ionic model, which smoothly interpolates between Debye-like and ideal-gas behavior, is employed to model contributions from atomic motion, and Thomas-Fermi-Dirac theory is used for contributions from thermal electronic excitations. Predictions for the compressibility, principle and porous shock Hugoniot, thermal expansion, heat capacity, and melt line are compared with experimental data. © 2012 American Institute of Physics.