1. Department of Chemistry, Institute of Technical and Macromolecular Chemistry, University of Hamburg, Bundesstrasse 45, 20146 Hamburg, Germany; Mechanical Engineering Department, University of Auckland, Private Bag 92019, Auckland, New Zealand; Institute of Structure Physics, Technical University of Dresden, 01062 Dresden, Germany; and HASYLAB at DESY, Notkestrasse 85, 22603 Hamburg, Germany