Structural investigations under high pressure conditions

Because of its extremely high yield strength, hardness and relatively high transparency to high-energy x-ray radiation, the diamond anvil cell has become a favored device in high pressure research. This includes structural investigations where pressure induced phase transitions can be studied using x-ray diffraction techniques up to several Mbars when combined with a high-brilliance synchrotron source. In this paper several structural studies under high pressure are presented to show general trends. High pressure instrumentation has reached the stage at which hydrogen, according to theoretical calculations, can be metallized and thermodynamic conditions, (i.e. pressure and temperature) exceed those at the center of the earth.