SCANNING TUNNELING MICROSCOPE-INDUCED MOLECULAR-MOTION AND ITS EFFECTON THE IMAGE-FORMATION

The effect of tip-induced molecular motion on the appearance of scanni ng tunneling microscope (STM) images of anthracene on Ag(110) was inve stigated for various tunneling parameters and at various temperatures. At 50 K, isolated molecules can be imaged at a high tunneling resista nce. For an increased tip-molecule interaction at a decreased resistan ce, apparent one-dimensional and two-dimensional molecular superstruct ures arise in the STM images that are due to an interplay between tip- induced motion, transient binding at specific substrate sites and repe ated imaging of a molecule. At an even higher tip-molecule interaction strength, molecules can be dragged over the surface such that an atom ically resolved substrate lattice is discernible. The slid molecule ac ts as an amplifier of the charge corrugation of the metallic surface. (C) 1998 Elsevier Science B.V. All rights reserved.