REORDERING OF SURFACE PHASES DURING ATOMIC-FORCE MICROSCOPY - A SIMULATION STUDY

Atomic force microscopy detects forces between a scanning tip and mole cules in the surface with which it is in contact. It is now widely use d to characterize surface structure. In many cases it has been possibl e to achieve atomic resolution, and atomic force microscopy can theref ore provide a very direct probe of molecular behavior at interface. We have used the molecular dynamics simulation of a Langmuir-Blodgett fi lm to study the effect of tip shape on the observed pattern and to exp lore whether the structure of the adsorbate is significantly changed b y the presence of the tip. Our results indicate that the presence of t he tip close to the film causes compression of the adsorbate and subse quent enhancement of the translational structure of the film by the sc anning tip and that the scanning results are sensitive to the tip geom etry.