RE3+ VUV d! f luminescence investigated by synchrotron radiation excitation at HASYLAB

Although known since many years, the vacuum ultraviolet (VUV) 4 f n $ 4 f n−15d transitions of heavier trivalent rare earth ions were investigated in detail only during the last decade. An essential prerequisite was synchrotron radiation as a tuneable source of photon excitation in the VUV range. Luminescence spectroscopy under state-selective VUV excitation turned out to be particularly useful to characterize the 4 f n $ 4 f n−15d transitions. Most of the progress has been achieved at the Hamburger Synchrotronstrahlungslabor HASYLAB with its unique VUV luminescence facilities. The experiments stimulated calculations for a deep understanding of the transitions. Results of the main groups involved at HASYLAB will be compared. Besides the achievements, limitations and restrictions of the experiments and of the theoretical models get obvious. This may help to stimulate future work. PACS: 78.55.-m, 71.38.-k, 32.10.-f 1