Model dependence of AFM simulations in non-contact mode

Pairwise summation of a Lennard–Jones type potential is, because of its simplicity, an attractive method for theoretical simulation of scan images in atomic force microscopy (AFM). However, a serious problem for such simulations is the uncertainty in the AFM tip–sample interaction. While the interatomic repulsion is more or less universal, the attractive component of the interaction can include van der Waals, ionic, dipole, chemical, electrical and other kinds of forces. In the present paper, the pairwise summation method for the simulation of AFM scans is analyzed against the uncertainties in the attractive component of the interaction potential. It is shown that the simulation method produces, qualitatively, similar images of an atomic surface for a broad range of possible contributions to the attractive force interaction. This indicates that the numerical method, while relatively insensitive to the explicit attractive force contributing to the tip–sample interaction, is suitable for theoretical simulations of atomic resolution in the AFM.