1. Department of Physical Chemistry, Faculty of Science, Palacký University Olomouc, tř. 17 listopadu 12,77146 Olomouc, Czech Republic
2. Regional Centre of Advanced Technologies and Materials, Faculty of Science, Palacký University Olomouc, Šlechtitelů 27, 78371 Olomouc , Czech Republic
3. Institute for Applied Physics, Eberhard Karls University of Tübingen, Auf der Morgenstelle 10, D-72076 Tübingen, Germany
4. Natural and Medical Sciences Institute at the University of Tübingen, Markwiesenstr. 55, D-72770 Reutlingen, Germany
5. Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria