Electron‐Induced Dynamics of Heptathioether β‐Cyclodextrin Molecules |
| |
| Authors: | Avijit Kumar René Heimbuch Kim S Wimbush Hasan Ate?çi Adil Acun David N Reinhoudt Aldrik H Velders Harold J W Zandvliet |
| |
| Affiliation: | 1. Physics of Interfaces and Nanomaterials, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands;2. Supramolecular Chemistry and Technology, MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands;3. Biomolecular Chemistry, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands |
| |
| Abstract: | Variable‐temperature scanning tunneling microscopy (STM) and spectroscopy (STS) measurements are performed on heptathioether β‐cyclodextrin (β‐CD) self‐assembled monolayers (SAMs) on Au. The β‐CD molecules exhibit very rich dynamical behavior, which is not apparent in ensemble‐averaged studies. The dynamics are reflected in the tunneling current–time traces, which are recorded with the STM feedback loop disabled. The dynamics are temperature independent, but increase with increasing tunneling current and sample bias, thus indicating that the conformational changes of the β‐CD molecules are induced by electrons that tunnel inelastically. Even for sample biases as low as 10 mV, well‐defined levels are observed in the tunneling current–time traces. These jumps are attributed to the excitations of the molecular vibration of the macrocyclic β‐CD molecule. The results are of great importance for a proper understanding of transport measurements in SAMs. |
| |
| Keywords: | charge transport cyclodextrins molecular dynamics scanning tunneling microscopy self‐assembled monolayers |
|
|
