1. Contribution from the Department of Chemistry and Laser Physics Centre, Research School of Physical Sciences and Engineering, Australian National University, Canberra ACT 0200, Australia, Department of Chemistry, University of Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium, and Local Spatio-Temporal Functions Laboratory, Frontier Research System, RIKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan