1. EaStCHEM School of Chemistry, The University of Edinburgh, David Brewster Road, Edinburgh, EH9 3FJ, Scotland, UK
2. ISIS Pulsed Neutron and Muon Source, STF Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxon, OX11 0QX, UK
3. School of Physics and Astronomy, The University of Edinburgh, Edinburgh, EH9 3JZ, Scotland, UK
4. Fakultät für Physik, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany