1. Department of Chemical Engineering, Imperial College, London SW7 2AZ, U.K.
2. Diamond Light Source, Didcot, Oxfordshire OX11 0DE, U.K.
3. Institute of Process Research and Development, School of Chemistry, University of Leeds, Leeds LS2 9JT, U.K.
4. Department of Chemistry, University of Reading, Reading RG6 6AD, U.K.
5. School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD, U.K.