1. School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, U.K., Department of Chemistry, University of Warwick, Coventry C4V 7AL, U.K., Institute of Biophysics, Academy of Sciences of the Czech Republic, v.v.i., Kralovopolska 135, CZ-61265 Brno, Czech Republic, and Laboratory of Biophysics, Department of Experimental Physics, Faculty of Sciences, Palacky University, tr. Svobody 26, CZ-77146 Olomouc, Czech Republic