1. Chemistry Department, Marquette University, Milwaukee, Wisconsin 53201-1881, USA
2. Univ Rennes, CNRS, IPR (Institut de Physique de Rennes)-UMR 6251, F-35000 Rennes, France
3. KU Leuven, Department of Chemistry, B-3001 Leuven, Belgium
4. Department of Chemistry, Missouri University of Science and Technology, Rolla, Missouri 65409, USA