Zeeman measurements of Pr 3+ centres in CaO and CaF 2

Abstract

Three Pr 3+ centres in two different crystal hosts have been studied by site selective laser spectroscopy and Zeeman spectroscopy with attention directed at the 3P 0, 3P 1 and 1I 6 crystal field level assignments. The 3H 4→ 3P 0 excitation line is readily identified in each case. For a tetragonal and a trigonal centre in CaF 2 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 1I 6 states. For the Pr 3+ centre in CaO there are two lines adjacent to that associated with the 3P 0 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 1I 6 states. The centre is shown to have orthorhombic symmetry and the energy levels for this centre are determined.