1. School of Chemistry, University of Bristol, Bristol BS8 1TS, United Kingdom
2. School of Physics, University of Bristol, Bristol BS8 1TL, United Kingdom
3. Central Laser Facility, Rutherford Appleton Laboratories, Oxford OX11 0QX, United Kingdom
4. Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
5. Department of Chemistry, University of Victoria, Victoria, British Columbia V8W 3V6, Canada