1. School of Chemistry, University of Birmingham, Birmingham B152TT, U.K.
2. Department of Chemistry, School of Chemical and Physical Sciences, Keele University, Staffordshire ST55BG, U.K.
3. Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, Berlin 12205, Germany
4. Diamond Light Source, Didcot, Oxfordshire OX11 0DE, England