1. Beijing National Laboratory for Molecular Sciences (BNLMS), CAS Key Lab of Colloid and Interface Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China, Angewandte Physikalische Chemie, Universität Heidelberg, Im Neuenheimer Feld 253, D-69120 Heidelberg (Germany), and Institute for Molecular Biophysics, University of Maine, Orono, Maine 04469