Calculation of the Casimir force between imperfectly conducting plates

The Lifshitz formalism for determining the attractive force between materia l bodies with generalized electromagnetic susceptibility is applied numeric ally to gold, copper, and aluminum. The deviation from the perfect conducti vity Casimir force approximately agrees with a first-order plasma model cal culation at large separation, but at separations corresponding to the plasm a frequency, deviations of over 50% from the first order model are found, w hile deviations from corrections up to second order are about 10%. These re sults are discussed in the context of recent measurements of the Casimir fo rce. [S1050-2947(99)50605-7]. PACS number(s): 12.20.Fv, 07.07.Mp.