1. Department of Materials and Environmental Chemistry, Stockholm University, SE-10691 Stockholm, Sweden
2. Condensed Matter Theory, Department of Physics, AlbaNova University Center, Royal Institute of Technology (KTH), 106 91 Stockholm, Sweden
3. Institute for Inorganic Chemistry, Leipzig University, Johannisallee 29, D-04103 Leipzig, Germany
4. Deutsches Elektronen-Synchrotron DESY, Notkestraße 85, D-22607 Hamburg, Germany
5. Theoretical Physics Division, Department of Physics, Chemistry and Biology (IFM) Linköping University, SE-581 83 Linköping, Sweden
6. Department of Physics and Astronomy, Uppsala University, SE-75120 Uppsala, Sweden