  Recent surface force apparatus (SFA) and atomic force microscopy (AFM) can
measure force curves between a probe and a sample surface in solvent. The force
curve is thought as the solvation structure in some articles, because its shape
is generally oscilltive and pitch of the oscillation is about the same as
diameter of the solvent. However, it is not the solvation structure. It is only
the force between the probe and the sample surface. Therefore, this brief paper
presents a method for calculating the solvation structure from the force curve.
The method is constructed by using integral equation theory, a statistical
mechanics of liquid (Ornstein-Zernike equation coupled by hypernetted-chain
closure). This method is considered to be important for elucidation of the
solvation structure on a sample surface.
