“…The vertically sectional force map along the horizontal line, indicated by a pair of counter arrows, even represents an atomic-scale contrast of the total interaction forces total , as shown in Figure 2(c), where the positions corresponding to the C1, C2, and H sites in Figure 2 In three-dimensional (3D) force field spectroscopy (3D-FFS), tip-sample interaction forces are measured by recording ∆ f (x, y, z) and converting that to F(x, y, z). At every recording point (x, y) over the sample surface, the tip-sample distance z is regulated to attain the same ∆ f value and consequently to obtain the surface topography as in the case of previous imaging with atomic resolution [28,32,33]. Acquisition of the atomically resolved topography, which also took place during the 3D-FFS measurement, allows for an atomic-site-specific analysis of interaction forces.…”