Infrared Transmission Spectra of Metallic ReO3

Infrared transmission spectra of metallic ReO 3 film deposited upon silicon plate have been measured in the region from 1200 to 30 cm -1 . Two structures are observed at 905 and 315 cm -1 at room temperature and assigned to the infrared active lattice vibrations of ReO 3 crystal. The force constants derived from the elastic constants support these assignments. Raman spectra of ReO 3 crystal were also measured and the results are consistent with those of infrared transmission. These results are compared with those of other transition metal oxides. Natures of the optically active lattice vibrations and the metal oxygen bonds in metallic ReO 3 are discussed.