1. Experimentalphysik II, Universität Bayreuth, D-95440 Bayreuth, Germany
2. Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, USA
3. Technische Mechanik und Strömungsmechanik, Universität Bayreuth, D-95440 Bayreuth, Germany
4. Institute of Complex Systems, Forschungszentrum Jülich, D-52425 Jülich, Germany
5. Institute of Physics, Kazan Federal University, Kazan 420008, Tatarstan, Russia