The calculation of retarded van der Waals interaction for practical applications

The effect of retardation in the van der Waals interaction between two spherical particles is examined theoretically. The expressions which can be applied to kappa a much greater than 1 and D > a are obtained, in which kappa is Debye-Hukel parameter,a is the radius of particles, D is the shortest distance between two spheres. An extensive comparison of exact, sophisticated and simplified treatments has been described. Computation results show that the improved approximations agree fairly well with exact computations and can be considered as the supplement of the classical Hamaker results. They should find application in problems of colloid stability and particle deposition.