Long Jumps of an Organic Molecule Induced by Atomic Force Microscopy Manipulation

Langewisch G, Falter J, Schirmeisen A, Fuchs H

Abstract

Non-contact atomic force microscopy at cryogenic temperatures is used for the controlled lateral manipulation of individual 3,4,9,10-perylene-tetracarboxylicacid-dianhydride (PTCDA) molecules on the Ag(111) surface. The molecules are moved along the [-110] direction of the Ag lattice in the regime of repulsive tip-molecule forces performing discrete jumps that span distances from single to multiple lattice spacings. The analysis of the two-dimensional force field measured before and during the manipulation reveals that the displacement beyond nearest neighbor sites cannot be explained by long range tip-molecule forces but instead has to involve an energy transfer to translational modes of the molecule. Combined with the results of the simultaneous measurement of the energy dissipation, these findings allow to identify a likely manipulation mechanism and provide insight into the process of energy transfer between excited large molecules and metal surfaces. Furthermore, implications for the theoretical treatment of NC-AFM based molecule manipulation are discussed.