Energy levels and crystal-field analysis of Tm3+ in YAl3(BO3)4 crystals

The electronic structure of the Tm3+ in YAl3(BO3)4 crystals has been investigated by means of low temperature absorption and emission spectroscopy in the 5000–30,000 cm−1 range. The assignment of the lines composing the observed manifolds to transitions between the Stark levels of Tm3+ is complicated by the presence of extra features having different origins. The energy levels scheme of the doping ion has been compiled after a careful analysis of the spectra by reproducing the observed transitions by means of theoretical calculations based on a Hamiltonian, including the free ion and the crystal field (CF) terms. The agreement between experimental and calculated energy values was reasonably good, the overall r.m.s. deviation being 16 cm−1. The resulting CF parameters have been tabulated and compared with those reported in literature for other rare earth ions doped in YAB. The analysis of trends observed along the lanthanide series evidences some inconsistencies and the necessity of a systematic investigation of these systems.