Crystal-field analysis of triply ionized rare earth ions in lanthanum trifluoride

Abstract

Previously reported spectra of nine triply ionized lanthanides in LaF₃ are analyzed by using a parametrized C₂ crystal‐field Hamiltonian. Initial crystal‐field parameters B_nm in the fitting procedure were obtained from point charge lattice sums A_nm using previously derived ρ_n, where B_nm=ρ_nA_nm. The largest rms deviation of theory from experiment was 18.1 cm⁻¹ (Pr³⁺), and the smallest was 2.1 cm⁻¹ (Ho³⁺). The resulting B_nm were used to obtain a smoothed set of crystal field parameters for the entire lanthanide series whose largest rms deviation was 20.8 cm⁻¹ (Pr³⁺) and whose smallest was 3.5 cm⁻¹ (Ho³⁺).