1. Surface Physics Division, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland
2. Quantum Physics Division, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznań, Poland
3. Laboratoire de Physique Theéorique et Modélisation, Université de Cergy-Pontoise, CNRS, UMR 8089 2, Av. Adolphe Chauvin, 95302 Cergy-Pontoise Cedex, France