Opposite parity 4fn-15d1 states of Ce3+ and Pr3+ in MSO4 (M=Ca, Sr, Ba)

Abstract Research on Ce 3+ and Pr 3+ in three different sulphate lattices reveal strong similarities regarding the 4f n −1 5d 1 level structure. The energy difference between the 4f 0 5d 1 levels of Ce 3+ and the 4f 1 5d 1 levels of Pr 3+ is in good approximation a constant value of 12 240±750 cm −1 . The crystal field splitting of the 4f n −1 5d 1 levels for Ce 3+ and Pr 3+ , doped in the same sulphate host, is comparable. The first 4f 1 5d 1 band of CaSO 4 :Pr 3+ is split in at least three levels. This is ascribed to splitting due to the spin–orbit interaction of the remaining electron in the 4f shell and to the electrostatic interaction between the 4f and the 5d electron.