Theoretical study of the VUV spectroscopy of Ce3+ and Tb3+ in BaBPO5 crystal using an empirical-ab initio hybrid method

The f-d transition of Ce3+ and Tb3+ in BaBPO5 was studied theoretically using the parametric Hamiltonian model. In order to overcome the difficulty in determining many of the parameter values, we adopted the model-space effective Hamiltonian method to determine the crystal-field parameters and spin-orbit parameters values. The method made use of the energies and eigenvectors, which were obtained from an ab initio calculation using the relativistic self-consistent discrete variational Slater software package (DV-Xa). Other parameters, which were less dependent on host crystals, were taken from published data. The calculated values of parameters were reasonable, and the energy-levels and f-d transition spectra agreed reasonably well with the measured excitation spectra of 5d-4f emission.