Why do atomic force microscopy force curves still exhibit jump to contact ?

The force between two particles as a function of distance is one of the most fundamental curves in physics. Here, we describe how the force feedback microscope can routinely measure the tip-surface interaction in the entire range of distances with a sensitivity of 1 pN and in different media. The method allows to measure simultaneously the force, force gradient, and damping from solely the knowledge of the lever spring constant. The jump to contact is avoided and thus it is possible to follow the brutal nucleation of a water bridge between the tip and the surface.