Energy levels of Dy3+(4f9) in orthoaluminate crystals

A detailed crystal-field splitting analysis is reported for the energy levels of Dy3+(4f(9)) in crystals of YAlO3 and DyAlO3 orthoaluminates. Experimental energy (Stark) levels for the 15 lowest-energy L-2S+1(J) multiplet manifolds of Dy3+ are reported and supplemented with values found in the literature. A parameterized Hamiltonian, including Coulombic, spin-orbit, configuration interaction, and crystal-field terms in C-s symmetry, was diagonalized for the H-6(J), F-6(J), F-4(J), I-4(J), and (4)G(J) states. Initial sets of crystal-field parameters were determined from lattice-sum calculations and the three-parameter theory. Considerable J-mixing is found for states having nearly the same energy such as the manifolds F-6(11/2), H-6(9/2), and F-6(9/2), H-6(7/2). Even states that are well separated from each other in energy show sufficient J mixing to explain the polarized absorption and Zeeman effects that involve transitions from the nearly pure (less than 0.2% J mixing) ground state, H-6(15/2) to excited states such as F-6(5/2) and F-6(3/2). The rms for 70 calculated-to-experimental Stark levels for Dy3+ in YAlO3 is 10 cm(-1); the rms for 43 calculated-to-experimental levels for Dy3+ in DyAlO3 is 8 cm(-1). (C) 2003 American Institute of Physics.