A new approach to the determination of lanthanide spin-correlated crystal field parameters

A simple technique for determining spin-correlated crystal field parameters from spectroscopic data, which depends on the superposition model, is developed. This avoids the need for detailed simultaneous fits to both free-ion and crystal field parameters and provides a practicable method for low-symmetry systems. New sets of parameters have been obtained for the systems Ho 3+ :YPO 4 , Er 3+ :YAlO 3 and Nd 3+ :PbMoO 4 . Similar results to those from the detailed fitting procedure were obtained for HO 3+ :LaCl 3 . The results conform that the rank-six spin-correlated crystal field contributes significantly to lanthanide crystal field splittings.