Raman and UV-visible absorption spectroscopy of rare-earth hydride under high pressure

Kume, Tetsuji*; Machida, Akihiko; Aoki, Katsutoshi; Sasaki, Shigeo*; Shimizu, Hiroyasu*

Raman and visible absorption spectra of rare earth trihydrides have been measured at high pressures, in order to investigate the structural and electronic phase transitions. The successive phase transitions of hcp-intermediatefcc phase were confirmed by Raman measurements. From the visible absorption experiments, the band gap energy was estimated. The gap closure was found to occur on the transition from the intermediate to the fcc phase.