1. Department of Chemistry University of Munich Butenandtstraße 5–13 81377 Munich Germany
2. Lumileds Phosphor Center Aachen (LPCA) Lumileds (Germany) GmbH Philipsstraße 8 52068 Aachen Germany
3. ESRF, The European Synchrotron 71 Avenue des Martyrs, CS40220 38043 Grenoble Cedex 9 France
4. Institute for Mineralogy, Crystallography and Materials Science Leipzig University Scharnhorststraße 20 04275 Leipzig Germany