1. Research Complex at Harwell, Rutherford Appleton
Laboratory, Didcot, Harwell OX11 0FA, U.K.
2. Department
of Chemistry, University College London, 20 Gordon Street, London WC1H 0AJ, U.K.
3. University of Manchester South, I13 OX11 0DE & School of Materials, University of Manchester, Manchester, Lancashire M13 9PL, U.K.
4. ESRF-The European Synchrotron, 71 Avenue des Martyrs, 38000 Grenoble, France
5. BP Chemicals, Conversion Technology Centre, HRTC-DL10 Saltend, Hedon, Hull HU12 8DS, U.K.