1. Center for
Polymers and Organic
Solids, University of California at Santa Barbara, California 93106-5090, United States
2. Department of Chemistry, Université Laval, G1K 7P4 Quebec City, Quebec,
Canada
3. Faculté des
sciences, Université de Genève, 30 Quai Ernest-Ansermet,
CH-1211 Geneva 4, Switzerland
4. Light Technology Institute, Karlsruhe Institute of Technology, Kaiserstrasse 12,
D-76131 Karlsruhe, Germany