High-temperature electron-band calculations

Self-consistent electron-band theories have by now succeeded in producing rather impressive agreement with experiment for the low-temperature low-pressure bulk properties of metals. An abundance of high-temperature high-pressure shock-compression data offers an excellent proving ground for extension and testing of these methods under more extreme conditions. One important problem in such an application is a treatment of the electronic excitations. This is the concern of the present paper. Finite-temperature self-consistent electron-band calculations were performed for temperatures up to 22000 K, using the test case of compressed metallic iodine. Electron-phonon coupling was neglected, and the structure assumed to be a rigid face-centered-cubic lattice. Results for the finite-temperature total electronic energy and pressure obtained by the fully self-consistent calculations were found to be in close agreement with model calculations based solely on the ground-state electronic density of states and Fermi-Dirac statistics. This suggests the possibility of the significant savings in computational effort for high-temperature equation-of-state band calculations suitable for comparison with shock-compression data.