OSCILLATORY SOLVATION FORCES - A COMPARISON OF THEORY AND EXPERIMENT

Measurements are reported for the oscillatory force between mica surfaces in octamethyltetracyclosiloxane (OMCTS). Improved experimental resolution is achieved by solid-state distance control and force measurement and by an automated data acquisition system. The period of the oscillations is measured to be 0.82 +/- 0.02 nm. Theoretical calculations are shown to quantitatively describe the magnitude of the force in the case of hard-sphere and Lennard-Jones models of the OMCTS molecule, with the period being 0.74 and 0.78 nm, respectively. A rigorous proof of the Derjaguin approximation is also given.