1. Department of Functional Nanomaterials, Institute of Physics, Savanoriu; 231, LT-02300 Vilnius, Lithuania, Division of Molecular Physics, Department of Physics, Chemistry and Biology, Linköping University, 58183 Linköping, Sweden, and Institute of Biochemistry, Johann Wolfgang Goethe-University, Max-von-Laue-Strasse 9, 60438 Frankfurt, Germany