First-principles calculations of solid and liquid aluminum optical absorption spectra near the melting curve: Ambient and high-pressure results

Abstract

We present ab initio calculations of the linear optical conductivity of heated Al at ambient pressure and at the conditions relevant for shock melting $(P\ensuremath{\sim}125\text{ }\text{GPa},\text{ }T\ensuremath{\sim}5000\text{ }\text{K})$. It is shown that the visible and near-UV optical spectrum is very sensitive to the phase (fcc solid versus liquid) of Al for both $P=0$ and 125 GPa. The ambient-$P$ results confirm an earlier prediction and the results of a recent experiment while the high-$(P,T)$ results allow us to conclude that in situ measurements of optical constants should be able to diagnose the shock melting of Al.