Quantitative analysis of dynamic-force-spectroscopy data on graphite(0001)in the contact and noncontact regimes

We present a comparative experimental and theoretical study of the frequenc y shift in ultrahigh vacuum dynamic force microscopy at 80 K on graphite(00 01) measured as a function of the tip-sample distance for different resonan ce amplitudes A in the repulsive and attractive regime of the tip-sample Fo rces. The resulting frequency shift versus distance curves scale with 1/A(3 /2) over the full range. We determined the tip-sample force from the freque ncy shift versus distance curves and found good agreement with specific for ce laws for long-range (van der Waals), short-range (Lennard-Jones), and co ntact (Hertz) forces.