The Supramolecular Approach and Total Interaction Energies

In the last section, we introduced methods which can be employed to calculate the total electronic energy Ea for a given molecule with fixed nuclei. The stepwise calculation of electronic energies for various nuclear configurations allows us to scan essential parts of the potential energy hypersurface (the so-called Born-Oppenheimer surface) on which nuclear motions and chemical reactions 

Interaction energies are thus well-defined, but more than one definition is possible as we shall see in the following. For modeling the interactions of molecules in a supramolecular assembly one may define a chemical reaction like 

The quantum chemical standard model for the inclusion of finite-temperature 

To conclude this section, we reprint in Table 12.1 a comparison of interaction energies for a hydrogen-bonded complex, which models interactions within amide ro- 

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