Surface interaction energy hyper

The thermodynamic treatment discussed so far employed the harmonic approximation. Its use for weak intermolecular interactions is, however, not entirely justified. With strong vdW molecules (of course, except strong hydrogen-bonded complexes, vide supra) we can hope that the anharmonicity (in connection with thermodynamic treatment) does not play a crucial role. There exists another complication concerning complexes possessing a double-minimum on energy hyper-surface. If the minima are separated by low energy barrier the harmonic approximation is not adequate . The role of anharmonicity is essential with true vdW molecules. Unfortunately, except for the H O... HF and (HjO), complexes no complete experimental thermodynamic characteristics are available for the for-... 

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