2.2.4.3 Appendices
1. Parabolic or spherical probe.
![](/data/media/images/spm_basics/scanning_force_microscopy_sfm/cantilever-sample_force_interaction/van_der_waals_force/appendices/img02.gif)
The model applies to probes with a spherical tip at small tip-sample separations
. The same result is obtained generally for the parabolic tip.
![](/data/media/images/spm_basics/scanning_force_microscopy_sfm/cantilever-sample_force_interaction/van_der_waals_force/appendices/img03.gif)
(1)
In AFM measurements with silicon probe and sample at
,
,
:
.
2. Conical probe.
![](/data/media/images/spm_basics/scanning_force_microscopy_sfm/cantilever-sample_force_interaction/van_der_waals_force/appendices/img08.gif)
The model applies in case when tip curvature radius can be neglected as compared to tip-sample separation (
).
![](/data/media/images/spm_basics/scanning_force_microscopy_sfm/cantilever-sample_force_interaction/van_der_waals_force/appendices/img10.gif)
(2)
In AFM measurements with silicon probe and sample at
,
,
:
.
3. Pyramidal probe.
![](/data/media/images/spm_basics/scanning_force_microscopy_sfm/cantilever-sample_force_interaction/van_der_waals_force/appendices/img08.gif)
The model applies in case when tip curvature radius can be neglected as compared to tip-sample separation (
).
![](/data/media/images/spm_basics/scanning_force_microscopy_sfm/cantilever-sample_force_interaction/van_der_waals_force/appendices/img14.gif)
(3)
In AFM measurements with silicon probe and sample at
,
,
:
.
4. Conical probe with a rounded tip.
![](/data/media/images/spm_basics/scanning_force_microscopy_sfm/cantilever-sample_force_interaction/van_der_waals_force/appendices/img16.gif)
The model is a generalization of (1) and (2) at arbitrary ratio between
and
.
![](/data/media/images/spm_basics/scanning_force_microscopy_sfm/cantilever-sample_force_interaction/van_der_waals_force/appendices/img19.gif)
(4)
where
. At
(semispherical probe) formula (4) transforms into formula (1) while at
(conical probe) – into formula (2).
In AFM measurements with silicon probe and sample at
,
,
:
.