Ternary Complexes, Clusters and Infinite Chains

In order to obtain a better understanding of the forces acting in molecular clusters we consider an appropriate partitioning of intermolecular energies. For the formation of an aggregate of these subsystems A, B and C 

1 Additive Binary Potentials ami the Role of Many-Body Forces 

In order to derive positive indications of the importance of many-body contributions to structures of clusters we compare some very general results with experimental data from systems which have structures sufficiently simple to allow a straightforward interpretation. Some crystals will be well suited for this purpose. 

In non-polar systems pair potentials can be simulated quite well by Lennard-Jones type functions  

De is the depth of the well in the potential curve and Re the equilibrium distance (Fig. 10). In the absence of many-body forces the energy of interaction in clusters is simply a superposition of expressions of type (8). For the trimer ABC, we have 

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