Critical Parameters, Thermodynamic Functions, and Shock Hugoniot of Aluminum Fluid at High Energy Density.

We present estimates of the critical properties, thermodynamic functions, and principal shock Hugoniot of hot dense aluminum fluid as predicted from a chemical model for the equation-of-state of hot dense, partially ionized and partially degenerate plasma. The essential features of strongly coupled plasma of metal vapors, such as multiple ionization, Coulomb interactions among charged particles, partial degeneracy, and intensive short range hard core repulsion are taken into consideration. Internal partition functions of neutral, excited, and multiply ionized species are carefully evaluated in a statistical-mechanically consistent way. Results predicted from the present model are presented, analyzed and compared with available experimental measurements and other predictions in the literature. A distinct feature of the predictions of the present model is the appearance of a third kink in the Hugoniot curve at a weaker shock strength which can be attributed to the successive ionization of the three electrons in the M shell.