Shock temperatures and melting in CsI

Abstract

Shock-temperature measurements have been made on CsI up to 10 800 K and 0.9 Mbar. Melting has been observed to occur at 0.25 Mbar and 3500 K. A simple model for melting based on the packing of soft spheres is shown to adequately describe the data. The results suggest that in the liquid along the freezing line there is a gradual pressure-induced change from an open NaCl-like structure to one in which atoms are arranged as in a close-packed monatomic fluid. Above 5000 K, electronic excitation is observed to occur due to the high shock temperatures generated and the narrowing of the CsI band gap under pressure.