Langmuir 1999, 15, 207-213
207
Computer Modeling of Atomic Force Microscopy Force Measurements: Comparisons of Poisson, Histogram, and Continuum Methods Forrest Stevens, Yu-Shiu Lo, Joel M. Harris, and Thomas P. Beebe, Jr.* Department of Chemistry, The University of Utah, Salt Lake City, Utah 84112 Received June 12, 1998. In Final Form: October 26, 1998 A computer model of the AFM pull-off process was used to test the Poisson method for calculating bond forces and to compare the Poisson and histogram methods of finding single-molecule bond-rupture forces. The Poisson method appeared to work well, producing accurate individual bond-rupture forces even in the presence of moderate to large amounts of different types of variations or noise, while the histogram method only produced good results at low noise levels, even with large sample sizes. Three cases were found where use of the Poisson model could lead to inaccurate measurement of individual bond forces, the most important being related to the bond-formation probability, which must be low (ideally