Approximate expression for interaction of a two-parallel-plane double layer at constant surface potential and constant surface charge

A fast convergent formula for the interactional energy between two parallel plates at constant surface potential and constant surface charge is derived by a simple method of the series expansion, and the numerical result of only the first five terms of the series is excellent for the dimensionless surface potential of colloidal particle <f>y0&les;4</f>. [Copyright &y& Elsevier]