For NC, changing the distance between the sample and tip to maintain a constant frequency gives the data. IC is more complicated since the tip passes from VDW forces to coulomb repulsion, but the NC description is still a good approximation if one realizes that additional energy will be lost when the tip taps the surface thereby reducing vibrating amplitude. This adds an additional attractive region that IC must penetrate and retract from. The nonlinearity is shown below. Back to the Research Section Back to the Homepage Written and maintained by Adrian Fehr.
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