Crystal-field and superposition model analysis of :BaY F ( = Er, Dy, Nd)

Abstract:

The experimental values of the energy levels of Er³⁺, Dy³⁺, and Nd³⁺ in BaY₂F₈ were fitted to a single-ion Hamiltonian containing free-ion and crystal-field interactions. The crystal-field parameters so evaluated were then analyzed by using Newman's Superposition Model. The agreement between the two sets of parameters is good, provided a possible distortion of the F^- polyhedron around the rare-earth site is taken into account. The effects of a possible displacement of the rare-earth ion substituting for Y³⁺ are also evaluated.