  In order to explore repulsive Casimir/van der Waals forces between solid
materials with liquid as the intervening medium, we analyze dielectric data for
a wide range of materials as for example PTFE, polystyrene, silica and more
than twenty liquids. Although significant variation in the dielectric data from
different sources exist, we provide a scheme based on measured static
dielectric constants, refractive indices, and applying Kramers Kronig (KK)
consistency to dielectric data to create accurate dielectric functions at
imaginary frequencies. The latter is necessary for more accurate force
calculations via the Lifshitz theory allowing reliable predictions of repulsive
Casimir forces.
