1. Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, U.K.
2. Physics Department, University of Warwick, Coventry CV4 7AL, U.K.
3. Physics Department E20, Technical University of Munich, James Franck Straße 1, D-85748 Garching, Germany
4. Department of Chemistry, Queen Mary University of London, Mile End Road, London E1 4NS, U.K.
5. Chemistry Department, University of Warwick, Coventry CV4 7AL, U.K.
6. Chemistry Department, University of Birmingham, University Road, Birmingham B15 2TT, U.K.