1. Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg, Germany, Laboratoire de Chimie-Physique, UMR 8000 CNRS & Université Paris-Sud 11, F-91405 Orsay Cedex, France, Laboratório de Espectroscopia e Laser, Instituto de Física, Universidade Federal Fluminense, 24210- 340, Niterói, RJ, Brazil, and Synchrotron SOLEIL, L’Orme des Merisiers, Saint Aubin - BP 48, F-91192 Gif-sur-Yvette, Cedex, France