Contact potentials in Casimir force setups: An experimental analysis

The authors present an extensive study of the contact potential difference, V-0, between a gold coated sphere and a gold coated plate kept in air at submicron separation. The data confirm that in ambient conditions, V-0 depends on both time and separation. They discuss the origin of the time dependence of V-0 and elaborate on its functional dependence on separation, d. The data strongly support a log(d) hypothesis but also show that in air this description is not quite complete. These effects might have important implications in the realm of Casimir force experiments. (C) 2010 American Vacuum Society. [DOI: 10.1116/1.3316583]