1. Dipartimento di Fisica and UdR CNISM, Università della Calabria, 87036 Arcavacata di Rende (CS), Italy
2. Department of Physiology and Biophysics, Aarhus University, Aarhus, Denmark
3. Max-Planck-Institut für biophysikalische Chemie, Abt. Spektroskopie, 37077 Göttingen, Germany