1. Institut für Experimentelle
und Angewandte Physik, Universität Regensburg, Universitätsstrasse 31, 93053 Regensburg, Germany
2. Macromolecular Chemistry
Group,
Chemistry Department and IfP, Bergische Universität Wuppertal, Gauss-Str. 20, 42097 Wuppertal, Germany
3. Department
of Physics and Astronomy, University of Utah, Salt Lake City, Utah 84112, United
States