1. Centre for Science at Extreme Conditions (CSEC) and School of Chemistry, The University of Edinburgh, EH9 3FD, UK
2. STFC Rutherford Appleton Lab, ISIS Facility, Harwell Science and Innovation Campus, Didcot, OX11 0QX, UK
3. Institut Laue-Langevin, 38042 Grenoble Cedex, France