1. Department of Chemistry, Swedish University of Agricultural Sciences, P.O. Box 7015, SE-750 07 Uppsala, Sweden
2. Department of Chemistry, Division of Structural Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
3. Department of Chemistry, University of Rome “La Sapienza”, Piazzale Aldo Moro 5, I-00185 Rome, Italy
4. European Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble Cedex, France