Energy levels of Dy3+(4f 9) in orthoaluminate crystals

Abstract

A detailed crystal-field splitting analysis is reported for the energy levels of Dy3+(4f9) in crystals of YAlO3 and DyAlO3 orthoaluminates. Experimental energy (Stark) levels for the 15 lowest-energy LJ2S+1 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 Cs symmetry, was diagonalized for the HJ6, FJ6, FJ4, IJ4, and GJ4 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 F11/26, H9/26, and F9/26, H7/26. 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, H15/26 to excited states such as F5/26 and F3/26. 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.