ZEEMAN MEASUREMENTS OF PR-3+ CENTERS IN CAO AND CAF2

Three Pr3+ centres in two different crystal hosts have been studied by site selective laser spectroscopy and Zeeman spectroscopy with attention directed at the 3P0, 3P1 and 1I6 crystal field level assignments. The H-3(4) --> 3P0 excitation line is readily identified in each case. For a tetragonal and a trigonal centre in CaF2 there is, in each case, a further weak excitation line higher in energy which exhibits a large Zeeman splitting. The associated excited levels are attributed to 1I6 states. For the Pr3+ centre in CaO there are two lines adjacent to that associated with the 3P0 state and although they do not exhibit linear Zeeman splittings, there are quadratic Zeeman shifts due to large off-diagonal terms. Again the related levels are attributed to 1I6 states. The centre is shown to have orthorhombic symmetry and the energy levels for this centre are determined.