1. Department
of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
2. Competence
Centre for Catalysis and Department of Physics, Chalmers University of Technology, SE-41296 Göteborg, Sweden
3. MAX
IV Laboratory, Lund University, Box 118, SE-221 00 Lund, Sweden
4. Division
of Synchrotron Radiation Research, Lund University, Box 118, SE-221
00 Lund, Sweden
5. Department
of Chemical Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway