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

Previously reported spectra of nine triply ionized lanthanides in LaF3 are analyzed by using a parametrized C2 crystal-field Hamiltonian. Initial crystal-field parameters Bnm in the fitting procedure were obtained from point charge lattice sums Anm using previously derived ρn, where Bnm=ρnAnm. 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 Bnm 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+).