1. Department
of Theoretical Physics, Faculty of Physics, Vilnius University, Sauletekio Avenue 9, LT-10222 Vilnius, Lithuania
2. Institute of Physics,
Center for Physical Sciences and Technology, Gostauto 11, LT-01108 Vilnius, Lithuania
3. Laboratory
of Biophysics, Wageningen University, P.O. Box 8128, 6700 ET Wageningen, The Netherlands