1. Department of Physical Chemistry 1, Centre of Chemistry and Chemical Engineering, Lund University, P.O. Box 124, S-221 00 Lund, Sweden, GKSS Research Centre, Max Planck Street, D-215 02 Geesthacht, Germany, Department of Chemistry, Surface Chemistry, Drottning Kristinas väg 51, Royal Institute of Technology, S-100 44 Stockholm, Sweden, and Product Development, AstraZeneca R&D Lund, S-221 87 Lund, Sweden