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