Excited-state relaxation dynamics of Cr3+ in YAl3(BO3)4

The room temperature excitation spectrum of luminescence of Cr3+ in the YA1(3)(BO3)(4) single crystal have been used to estimate the crystal-field strength Dq and the Racah parameters B and C. The Dq/B = 2.4 value indicates that dopant ions occupy strong-crystal-field sites. Emission spectra of Cr3+ are consistent with a strong-crystal-field case in which the ZE excited state is the lowest. The influence of temperature on the R-1 line position has been examined and it has been found that the thermal line shift is consistent with predictions derived from consideration of ion-phonon interaction. The influence of temperature on emission lifetime in the 5-300 K temperature range has been analysed. In doing this, the energetic structure of Cr3+, consisting of the ground-analysed. and excited electronic manifolds mixed by the spin-orbit interaction, has been constructed using the diabatic representation. An expression for the total probability of the depopulation of luminescent states was next derived and fitted to experimental data yielding the E-2-T-4(2) separation energy Delta = 730 cm(-1) and the T-4(2) radiative lifetime to tau(0) = 18.9 mus.