COMPRESSION OF KLOCKMANNITE, CUSE

Copper selenide (CuSe) was compressed in a diamond anvil cell at room temperature up to a pressure of 52 GPa and studied using energy disper sive x-ray diffraction and Raman spectroscopy. CuSe is nearly isostruc tural with copper sulfide (CuS), and a previous study indicates that c opper sulfide undergoes reversible pressure-induced amorphization at 1 8 GPa. The intensity of the x-ray diffraction peaks for CuSe decrease slowly, however, they never completely disappear up to a pressure of 5 2 GPa. The third-order Birch-Murnaghan equation of state fit to the da ta yields K-0 = 96.9 +/- 5.3 GPa and K-0' = 4.1 +/- 0.5. Vinet's unive rsal equation of state yields essentially identical parameters. Raman spectroscopy demonstrates that upon compression, the S-S bond in CuS c ompresses differently than the Se-Se bond in CuSe, possibly accounting fur the different high pressure behavior of these two very similar co mpounds. (C) 1998 American Institute of Physics.