Crystal-field analysis for RE3+ ions in laser materials: I. Absorption spectra and energy levels calculations for Nd3+ and Pr3+ ions in ABCO4 crystals

► Polarized absorption spectra measured for Nd 3+ and Pr3+ ions in ABCO4 crystals. ► Energy levels analyzed in terms of the free-ion and crystal field (CF) parameters. ► The B¯k parameters and the power law exponents tk of SPM model are determined. ► The energy levels of Nd3+ at triclinic C1 symmetry site successfully simulated.