X-Ray Absorption Spectroscopy of the Rare Earth Orthophosphates

Abstract

ABSTRACTX-ray Absorption Spectroscopy (XAS) of the Rare Earth (RE) 3d levels yields sharp peaks near the edges as a result of strong, quasi-atomic 3d104fn→3d94fn+1 transitions and these transitions exhibit a wealth of spectroscopic features. The XAS measurements of single crystal REPO4 (RE = La, Ce, Pr, Nd, Sm, Eu, Gd, Th, Dy, Er) at the 3d edge were performed in the total yield mode at beam line 8–2 at the Stanford Synchrotron Radiation Laboratory (SSRL). The XAS spectra of the RE ions in the orthophosphate matrix generally resemble the XAS of the corresponding RE metal. This is not unexpected and emphasizes the major contribution of the trivalent state to the electronic transitions at the RE 3d edges. These spectra unequivocally identify the transitions originating from well-characterized RE cores and correlate well with previous theoretical investigations.