INTERPRETATION OF THE OPTICAL-ABSORPTION SPECTRUM AND OF THE PARAMAGNETIC-SUSCEPTIBILITY OF NEODYMIUM A-TYPE SESQUIOXIDE

A-Nd2O3 is a layer structure built on the (NdO) nn+ cation. Data for the 4.2 K optical spectrum and the strongly anisotropic parallel and perpendicular paramagnetic susceptibilities between 4 and 1000 K measured on single crystals, are reproduced using a Hamiltonian, that involves 12 free atom parameters (three Racah's parameters, the spin-orbit coupling constant, Trees' parameters α and β, and Judd's six Tk operators) and six C3v crystal field parameters. The Hamiltonian operates on the 364 kets in 4f3, that is including J mixing. 88 Stark levels (from 0 to 34 000 cm-1) were fitted to a mean square deviation of 17 cm-1. The crystal field parameters (Wybourne's formalism) are B02 = -836 cm -1, B04 = 634 cm-1, B 34 = -1606 cm-1, B06 = 752 cm-1, B36 = 237 cm-1, B 66 = 672 cm-1. The spectrum is strongly displaced to the red with respect to Nd3+ in LaCl3 and this is due to a lowering of Slater's integrals F2 and F4 by 2% to 3%. The F6 integral is unchanged. The spin-orbit coupling constant is also lowered by 2%. The interaction parameters are slightly affected. © 1979 American Institute of Physics.