Fig. 2.

Crystal field splittings. Energy versus 2〈J_z〉 for the crystal field states of the ground ⁶H_15/2 multiplet for 1Dy and 2Dy corresponding to the CF parameters in Table 1. In the center panel, showing the eight Kramers doublets, the black arrows denote the observed INS transitions, while the grey arrows denote the individual transitions observed for the ⁴F_9/2→⁶H_15/2 emission line. Of the latter type, the multi-headed arrows denote the four excited doublets fully or partially assigned to the broad maximally intense band in the luminescence spectra of 1Dy (Fig. 3a), and 2Dy (Fig. 3b)