Short range interactions generally

End-to-end distances are parameters that are easy to calculate by theoretical approaches but cannot be measured directly. On the other hand, the radius of gyration is a quantity readily accessible by experiment. For M —4 < general relationships exist between the radius of gyration and the end-to-end distance for all linear chains with only short-range interactions, for example = 6 . 

A number of techniques have been employed to model the framework structure of silica and zeolites (Catlow Cormack, 1987). Early attempts at calculating the lattice energy of a silicate assumed only electrostatic interactions. These calculations were of limited use since the short-range interactions had been ignored. The short-range terms are generally modelled in terms of the Buckingham potential,... 

Separation of the effects due to the long-range and short-range interactions greatly advances the understanding of the dynamics prevailing in continuum processes. Particularly useful general theoretical frameworks to this effect have been the R-matrix theory [44, 70] and the multichannel quantum defect theory (MQDT) [71, 72], They have been applied successfully to a wide variety of atomic and molecular systems, and the relevant material is too rich to be covered in this article. 

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