1. Centre
for Theoretical and Computational Chemistry (CTCC), Department of
Chemistry, University of Oslo, P.O. Box 1033 Blindern, NO-0315 Oslo, Norway
2. Institut
des Sciences Chimiques de Rennes, École Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS
50837, 35708 Rennes
Cedex 7, France