1. Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43 Prague, Czech Republic
2. Dipartimento di Scienza ed Alta Tecnologia, Universitá degli Studi dell’Insubria, via Valleggio 9, 22100 Como, Italy
3. Institute for Computational Physics, University of Stuttgart, D-70569 Stuttgart, Germany