1. Surface Science Laboratory, Faculty of Engineering and Natural Sciences, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland
2. Liquid Sun Ltd., Tekniikankatu 1, FI-33720 Tampere, Finland
3. Faculty of Engineering and Natural Sciences, Tampere University, P.O. Box 692, FI-33014 Tampere, Finland