1. Department of Chemistry, The Lundbeck Foundation Center for Theoretical Chemistry and Center for Oxigen Microscopy and Imaging, University of Aarhus, Langelandsgade 140, DK-8000 Aarhus C, Denmark, Department of Chemistry, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway, and Department of Chemistry, Middle East Technical University, 06531 Ankara, Turkey