Determination of Tip-Sample Interaction Potentials by Dynamic Force Spectroscopy

We introduce a new method which allows the precise determination of the tip-sample interaction potentials with an atomic force microscope and avoids the so-called ``jump to contact'' of the tip to the sample surface. The method is based on the measurement of the resonance frequency as a function of the resonance amplitude of the oscillated cantilever. The application of this method to model potentials and to experimental data, obtained for a graphite sample and a silicon tip in ultrahigh vacuum, demonstrates its reliability.