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ION–SOLVENT INTERACTIONS 133

or in numerical form:

Substitution of in Eq. (2.110) gives which, when used in Eq. (2.109),
gives the vibrational contribution to the entropy of an NSCW near ions (Table 2.19).

2.15.13.6. (Model A). In this model, the hydrogen-bonded molecule of
the SB region is seen as executing one free rotation about the H-bond axis. The two
rotations about the axes perpendicular to the H-bond axis will be librational.
can be obtained from Eq. (2.109) using a frequency represented by a
wave-number of 60 assigned for the rotational band of a
one-hydrogen-bonded species. Thus,

The entropy corresponding to two librations can be obtained by inserting the
librational frequencies, and in Eq. (2.109). The assignments of these
based on the interpretation of the infrared spectrum for two libration frequencies, are
Substituting these values in Eq. (2.109) gives

The three vibrations, corresponding to the three translational degrees of freedom,
for a molecule involved in a single H bond are assigned frequencies of
The entropy for these vibrations follows from Eq. (2.109) as

From Eqs. (2.119) to (2.122)

Thus