Amorphous near-neighbor atom

Fig. 18 An example of how structural constraints may impose near-degeneracy on the site-occupation energies of neighboring interstitial sites in an amorphous solid. The host atom tetrahedra defining the interstitial sites a, b, c, d all have the edge 1-2 as a common structural feature. As a consequence, near degeneracy of sites a and d, for example, only involves a near-similarity in the arrangement of pairs 3-4 and 3-5.

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