1. Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
2. Queen Mary University of London, School of Biological and Chemical Sciences, Mile End Road, London E1 4NS, United Kingdom
3. Central Laser Facility, STFC Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, United Kingdom