Sign of the Casimir-Polder interaction between atoms and oil-water interfaces: Subtle dependence on dielectric properties

摘要

We demonstrate that Casimir-Polder energies between noble gas atoms (dissolved in water) and oil-waterninterfaces are highly surface specific.Both repulsion (e.g., hexane) and attraction (e.g., glycerine and cyclodecane)nis found with different oils. For several intermediate oils (e.g., hexadecane, decane, and cyclohexane) bothnattraction and repulsion can be found in the same system. Near these oil-water interfaces the interaction isnrepulsive in the nonretarded limit and turns attractive at larger distances as retardation becomes important. Thesenhighly surface specific interactions may have a role to play in biological systems where the surface may be morenor less accessible to dissolved atoms.