Shock Compression of Argon and Xenon. IV. Conversion of Xenon to a Metal-Like State

Abstract

Experiments have been reported in which liquid argon and xenon have been shock-compressed up to two to three times their initial densities. An inspection of the two sets of data indicates a surprisingly large compressibility in xenon at high temperatures and compression. The results of calculations for argon and xenon indicate that the energy gap between the filled valence band and empty conduction band in xenon is decreasing rapidly with increasing density. Using these results, a theoretical Hugoniot curve has been calculated that is in good agreement with experiment. On the basis of these results, we conclude that the highest pressure xenon points, which are at 500 kbar and 18 000°K, represent a metallic-like form of xenon that is similar to cesium. This state is one in which the conduction bands are partially filled as in a metal, and it has been reached by a combination of temperature and compression.