Atomic Parameters for the 4Fn-15D Configurations of Nd3+ and Er3+ Ions in Crystals

Matrix elements of spin-orbit interaction, nephelauxetic parameters beta(k) (k = 2, 4, 6), and radial expectation values < r(k)>(4f) have been evaluated semi-empirically for the excited configurations 4f(N-1)5d of the Nd3+ and Er3+ ions doped in crystals. It comprise the crystals as CaF2, LiYF4, YPO4, Y3Al5O12, Cs2NaYF6, Cs2NaErCl6, and K3YF6. The < r(k)>(4f) values have been determined by the dielectric screening model. The obtained results were compared with those for the ground 4f(N) configurations of the same ions. It has been concluded that the wave functions of the 4f(N-1) core electrons are more extended than those reported in theoretical studies.