\textit{Ab initio} calculations of principal and release isentropes for aluminum*

We present a direct first-principles approach to calculating isentropes using quantum molecular dynamics (QMD) simulations with density functional theory. The results are compared to several popular EOS models for aluminum as well as principal isentrope and release data from several sources. The agreement with data for aluminum is very good, as is agreement with aluminum data on the principal Hugoniot up to 1200 GPa. We find that our QMD isentropes and Hugoniot for aluminum represent a better overall match to available data than any of the existing aluminum equations of state. We have employed these methods to perform \textit{ab initio} impedance matching calculations for aluminum flyer plates impacting a deuterium sample.