MEASUREMENTS AND SIMULATION OF THE ZEEMAN SPLITTING IN NDOCL AND ND3+LIYF4

Measurements and simulation of the Zeeman effect in NdOCl and 1% Nd3+: LiYF4 single crystals were carried out. The rare earth local symmetrie s are C-4v and D-2d respectively. The isomorphism between these two po int groups allows discussion on symmetry assignments. The attention is focused on the (4)G(7/2) and (4)G(9/2) levels for NdOCl and on the F- 4(9/2) and (4)G(7/2) levels for Nd3+:LiYF4, because they are represent ative of the general splitting behaviour. We have first revisited the simulation of the energy level scheme in order to deal with confident wave functions. In the experimental magnetic field (B) range we have o btained linear, non-linear, undefined crossing and anti-crossing level s. These features depend on the orientation of B, on the irreducible r epresentation and on the transition closeness. The line widths have be en the main obstacle in confirming crossing regions, because their ave rage values are 8 cm(-1) at liquid helium temperature. The simulations were performed by introducing the magnetic Hamiltonian mu(B)(L + g(e) S) in the secular determinant before diagonalisation, A magnetic accid ental degeneracy is considered when discussing the crossing and anti-c rossing cases.