Distance geometry intermolecular contacts

Many other intermolecular and intramolecular contacts are described by distances (hydrogen bond lengths, van der Waals contact, experimentally determined distances from nuclear Overhauser effect (NOE) spectra, fluorescence energy transfer, etc.) so that the distance matrix representation can be used to specify all the known information about a molecular structure. These bounds are entered into a distance geometry program, as are other bounds that specify constraints on modeling problems, such as constraints to superimpose atoms in different molecules. Hypotheses about intra- or intermolecular conformations and interactions are easily specified with distance constraints models can be built quickly to test different hypotheses simply by changing the distance constraints. 

Compared witii other direct force measurement teclmiques, a unique aspect of the surface forces apparatus (SFA) is to allow quantitative measurement of surface forces and intermolecular potentials. This is made possible by essentially tliree measures (i) well defined contact geometry, (ii) high-resolution interferometric distance measurement and (iii) precise mechanics to control the separation between the surfaces. 

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