1. Institut für Physikalische Chemie, Universität Hamburg, Grindelallee 117, D-20146 Hamburg, Germany
2. HASYLAB, DESY, Notkestrasse 85, D-22603 Hamburg, Germany
3. School of Chemistry, University of Melbourne, Parkville, VIC 3010 Australia
4. ANSTO, Menai, NSW 2234 Australia