Energy-Level Scheme for Nd3+ in CaWO4

The free ion parameters obtained from a least-squares fit to the six lowest free ion levels of Nd3+ in CaWO4, neglecting configuration mixing, are (in cm−1): E1 = 4859.7, E2 = 24.78, E3 = 482.0, and ζ = 873.8. The rms deviation of this fit was 21. Crystal-field parameters appropriate to S4 symmetry were fit to the structure of the I9/24 and I11/24 levels. Intermediate coupling wavefunctions obtained from the free ion fit were used. J−J mixing between the I9/24 and I11/24 states was considered. The crystal-field parameter values found are (in cm−1): B02 = 514.2, B04 = −1040.0, B06 = − 60.0, B44 = − 1071.6, B46 = − 980.0, B4′4 = 16.4, and B4′6 = 13.1. The rms deviation of this fit was 9.5. We calculate the ground-state g values to be g‖ = 1.633 and g⊥ = 2.621. The corresponding experimental values are 2.035 and 2.537. By changing the Bmn we can get a better g-value fit, namely, 2.025 and 2.593.