1. Surface Science Group, Faculty of Engineering and Natural Sciences, Tampere University, FI-33014 Tampere, Finland
2. Competence Centre for Catalysis and Department of Physics, Chalmers University of Technology, SE-412 96 Göteborg, Sweden
3. Photonic Compounds and Nanomaterials Group, Faculty of Engineering and Natural Sciences, Tampere University, FI-33014 Tampere, Finland
4. Faculty of Engineering and Natural Sciences, Tampere University, FI-33014 Tampere, Finland