1. Photochemical Dynamics Group, Ecole Polytechnique Fédérale de Lausanne; CH-1015 Lausanne Switzerland
2. Department of Chemical and Biomolecular Engineering; National University of Singapore; Singapore
3. Laboratory for Photonics and Interfaces; Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne; CH-1015 Lausanne Switzerland