title: Intramolecular Force Contrast and Dynamic Current-Distance Measurements at Room Temperature.
abstract: Scanning probe microscopy can be used to probe the internal atomic structure of flat organic molecules. This technique requires an unreactive tip and has, until now, been demonstrated only at liquid helium and liquid nitrogen temperatures. We demonstrate intramolecular and intermolecular force contrast at room temperature on PTCDA molecules adsorbed on a Ag/Si(111)-(√[3]×√[3]) surface. The oscillating force sensor allows us to dynamically measure the vertical decay constant of the tunneling current. The precision of this method is increased by quantifying the transimpedance of the current to voltage converter and accounting for the tip oscillation. This measurement yields a clear contrast between neighboring molecules, which we attribute to the different charge states.
authors: Institute of Experimental and Applied Physics, University of Regensburg, 93053 Regensburg, Germany.
authors: F
authors: F
authors: Huber
authors: Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193 Bellaterra, Spain.
authors: S
authors: S
authors: Matencio
authors: Institute of Experimental and Applied Physics, University of Regensburg, 93053 Regensburg, Germany.
authors: A J
authors: AJ
authors: Weymouth
authors: Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193 Bellaterra, Spain.
authors: C
authors: C
authors: Ocal
authors: Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193 Bellaterra, Spain.
authors: E
authors: E
authors: Barrena
authors: Institute of Experimental and Applied Physics, University of Regensburg, 93053 Regensburg, Germany.
authors: F J
authors: FJ
authors: Giessibl