Calculation of the Casimir force between imperfectly conducting plates

The Lifshitz formalism for determining the attractive force between material bodies with generalized electromagnetic susceptibility is applied numerically to gold, copper, and aluminum. The deviation from the perfect conductivity Casimir force approximately agrees with a first-order plasma model calculation at large separation, but at separations corresponding to the plasma frequency, deviations of over 50% from the first order model are found, while deviations from corrections up to second order are about 10%. These results are discussed in the context of recent measurements of the Casimir force. [S1050-2947(99)50605-7]. PACS number(s): 12.20.Fv, 07.07.Mp.