Simulation of optical and magnetic properties of neodymium (4f(3)) in the solid state: extreme sensitivity to the wave vector's composition

The optical absorption spectra of neodymium at 4 K are reproduced with a ve ry good agreement between calculation and experiment (15 < rms < 20 cm(-1)) . The wavefunctions which are obtained as a result of the energy calculatio n can be used to compute other physical properties. Among them we consider the paramagnetic susceptibility and the electron paramagnetic resonance. We report the results of these calculations concerning six compounds (Nd2O2S, A-Nd2O3, NdOCl, NdOF, Nd3+:LaCl3 and NdF3) for which the optical absorptio n spectra were thoroughly interpreted. We notice that these properties, dep ending on the point symmetry of the neodymium, are very sensitive to the va lues of the coefficients of the kets in the wavefunctions. These wavefuncti ons are extremely dependent on the crystal field parameters (cfps). A regar d on the magnetic properties is very useful to determine if a set of crysta l field parameters which fits the overall Stark levels is also convenient f or the ground state (I-4(9/2)) A comparison is also made between cfps deter mined from atomic positions in the structure (Simple Overlap Model) and phe nomenological cfps. We also consider the effect of the spin-correlated crys tal field (SCCF) through the action of its radial contribution represented by the c(k) parameters (k = 2,4,6). (C) 2001 Elsevier Science B.V. All righ ts reserved.