Simulations of force microscopy scanning on Calcite:

Contribution from A. Foster, R. Nieminen (Finland):

Snapshots from atomistic simulations of AFM scanning of the molecular solid calcite (CaCO3 ) at about 0.2 nm tip-surface separation with a positive potential ionic tip. The simulations show that the original (1) configuration of the carbonate group is strongly influenced by the tip's position. Initially as the tip passes from the leftside, the whole carbonate group spins to the right and displaces up (2). However, the strong repulsion between the tip apex and the highest O atom at very close range forces the group back into the surface, and it eventually spins to the left as the tip moves over the in plane O atom (3).

See also: Diploma Thesis from Urs Wyder