Simulation of SFM Images of Adsorbed C 60 and C 70 Molecules

The operation modes of the scanning force microscope (SFM) are sensitive to a number of different physical aspects related to the interaction between a very sharp probe tip and a corrugated sample. Understanding the physical processes at the origin of the image formation requires a specific model adapted to the low symmetry of the tip-sample system. In this paper, we describe the interaction between a probe tip composed of n atoms and fullerene molecules (C 60 and C 70 ) adsorbed on a surface. The long range part (van der Waals) of the interaction is determined by a self-consistent procedure which accounts for many-body effects to all orders. Short range (repulsive) interactions are then included by adding an atom-atom semiempirical pairwise potential. Simulations of SFM images of C 60 and C 70 adsorbed molecules are presented in two different modes of imaging.