CRITICAL COMMENTS ON THE NONLOCAL DIELECTRIC FUNCTION EMPLOYED IN RECENT THEORIES OF THE HYDRATION FORCE

In several recent theories of the hydration force based on nonlocal electrostatics, the nonlocal dielectric function is assumed to have a simple monotonic dependence upon the wavelength k. Here it is shown that the functional form assumed is seriously inconsistent with exact expressions for multipolar models. Since the erroneous form is essential to the predicted exponential decay of the hydration force, it would appear that theoretical treatments in which it is employed are without solid foundation. © 1990.