  Recent atomic force microscopy (AFM) can measure force curves between a probe
and a sample surface in several solvents. The force curve is thought as the
solvation structure in some cases, 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 just only a mean force
between the probe and sample surface. Since theoretical relation between the
mean force and the solvation structure had not been clearly known, we have
recently derived a relational expression within a simple liquid. Although we
have derived the relational expression within the simple liquid, the relational
expressions for a binary solvent and a molecular liquid have still not known
clearly. Hence, we try to obtain the relational expressions in the two types of
the solvents. In this letter, we briefly derive the relations and explain a
method for comparing the mean force measured by liquid AFM and the solvation
structure (obtained by a simulation, a liquid theory, or a x-ray reflectivity).
The derivations of the relational expressions are performed in the basis of
classical statistical mechanics of liquid.
