1. Physics Department, Institute for Energy Technology, P.O. Box 40, NO-2027
Kjeller, Norway
2. Dipartimento
di Chimica IFM
and NIS, Università di Torino, Torino,
Italy
3. Center for Materials
Crystallography,
Interdisciplinary Nanoscience Center and Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus
C, Denmark