A STUDY OF THE CALCITE CLEAVAGE PLANE USING THE ATOMIC-FORCE MICROSCOPE

We have recorded atomic resolution images on the (101BAR1) calcite cle avage plane using the atomic force microscope (AFM) with relatively hi gh tracking forces of the order of 10(-8) Newtons. The linear dimensio ns from the AFM image show a small difference (less-than-or-equal-to 1 0%) from the linear dimensions projected from the X-ray diffraction da ta using the morphological cleavage rhombohedral cell as a basic model . However, the average value of the angular dimension 'D', which is th e angle between the projecting nearest oxygen atoms and the next neare st oxygen atoms on the surface, shows a difference of 40% from the exp ected model value. This difference is most likely due to the possible different orientations of some surface carbonate groups. The fact that we could obtain atomic resolution with high tracking forces in our ex periments is most likely because of the multi-atom nature of our tip, which would reduce the effective force per atom.