ABSORPTION AND ZEEMAN-EFFECT IN ND3-DOPED LIYF4 - MEASUREMENTS AND SIMULATION()

The Nd3+ ion energy level scheme in a LiYF4 crystal host is re-examine d by absorption spectroscopy and Zeeman measurements. Some other Krame rs doublets have been observed. A total of 137 experimental levels has been input in the fitting procedures before the application of the ma gnetic field. The calculations were performed assuming the approximate D-2d rare-earth site symmetry, and the correct S-4, With all paramete rs varying freely. In both symmetries we have obtained a rms deviation of 17.7 cm(-1). In the presence of a magnetic field B, linear and non -linear anticrossing degeneracy lifting, together with negligible Kram ers degeneracy lifting, has been observed. In particular, with B perpe ndicular to c, the third component of the (4)G(7/2) level behaves in t he former way with a splitting of 22 cm(-1), for B = 6.3 T, and (4)G(5 /2) behaves in the latter way (B parallel to c). It was possible only to describe these features all together by introducing the magnetic Ha miltonian mu B(L + g(e)S) in the secular determinant before diagonaliz ation. Then, the 364 eigenstates and eigenfunctions of the 4f(3) confi guration are calculated. The isolated doublets in the energy level sch eme and having a small value of the g-factor, split linearly. In this situation, the framework of perturbation theory was used to obtain sat isfactory splitting s-factors. Those not isolated or with a large g-fa ctor have a non-linear anticrossing behaviour. The splitting of the lo west component of the I-4(9/2) ground-state multiplet is observed thro ugh a transition which is present in the lowest Zeeman component of th e F-4(7/2) level. This is quite well reproduced by the simulation.