Theoretical estimates of vibronic transition rates for Pr+3 in different host lattices

Recently, one of us developed a theoretical approach to estimate the vibronic intensity in the spectra of rare-earth (RE) ions. This model takes into account the dynamic coupling (DC) and forced eletric-dipole (ED) contributions to the vibronic intensity. An important aspect in this approach is that the contributions from DC and ED mechanisms can be analysed individually and may have opposite signs. Considering that the vibronic transitions of Pr+3 are not well described by the existing theories, it seemed worthwhile applying the present model to the Pr+3 case. The calculations were carried out to the P-3(0) --> H-3(4) transition of pr(+3) in the isostructural compounds LiYF4, Na5La(WO4)(4) and Na5La(MoO4)(4). The theoretical estimates of the vibronic rates are in fair agreement with the experimentally observed dependence on the host lattice and on the RE ion.