Raman and absorption spectrophotometric studies of selected lanthanide, californium-doped lanthanide, and actinide trihalides in the solid state

The solid-state absorption spectra of californiuin(III) ions as a dopant in a variety of lanthanide tribalide host matrices (LnCl₃: Ln = Ce, Sm, and Y; LnBr₃: Ln = Ce, Sm, Tb, and Y; Lnl₃: Ln = Ce and Y) have been recorded. The absorption spectra of the Cf(III) species have been correlated with the various crystal structures to support the use of solid-state absorption spectrophotometry as a tool for the identification of crystal structure

The phonon Raman spectra and the solid-state absorption spectra of PmF₃, PmCl₃, PmBr₃, and two previously unreported crystal modifications of Pml₃ have been recorded. Tentative symmetry assignments have been made for the observed Raman-active bands for these tribalides and also the sesguioxide. The room-temperature solid-state absorption spectra have been correlated to crystal field effects of the various metal ion site symmetries found in the crystal structures exhibited by these compounds.

The symmetry assignments of the Raman-active phonon modes have been made based on polarized Raman spectra from single crystals of YF₃ -type orthorhombic TbF₃ and PuBr3-type orthorhombic NdBr₃.

Raman spectra of other isostructural lanthanide compounds have been recorded and compared. Symmetry assignments for these compounds have been made by analogy to the single-crystal assignments. Raman spectra have been obtained and catalogued for a number of actinide compounds. Symmetry assignments have been made for the observed Raman-active phonon bands in this work based on the assignments made for isostructural lanthanide compounds.