Studies on CsBr with Synchrotron Radiation Under Ultrahigh Pressure up to 115GPa

In situ high pressure energy dispersive x-ray diffraction experiments have been carried out on CsBr by using diamond anvil cell device with synchrotron radiation source. The maximum pressure is 115 GPa. The structure of CsBr is changed from simple cubic phase to tetragonal phase at pressure about 53 GPa, marked by the splitting of its strongest diffraction line (110). At pressure above 98GPa, the color change of CsBr from transparent to red-brown was observed. No pressure-induced transition from insulator to metal is found at higher pressure up to 115GPa.