Crystal-field analysis of triply ionized lanthanides in Cs2NaLnCl6

Abstract

Optical spectra of the elpasolite hexachloride compounds Cs₂NaLnCl₆, where Ln represents one of the lanthanide ions, are analyzed with a crystal‐field Hamiltonian of O_h symmetry. Crystal‐field parameters, B_nm, are found that minimize the rms deviation between calculated and experimental energy levels for Ln=Ce, Pr, Nd, Eu, and Tb. A set of ’’smoothed’’ B_nm is found for the lanthanide series that predicts the spectroscopic properties of the remaining eight lanthanide ions. Predicted energy levels and g values are compared with available experimental data for all the lanthanides except Pm and Gd, and magnetic dipole intensities are computed.