Valence crystals electronic dislocations

The strong bonding in valence crystals results in the failure of these crystals to demonstrate, on irradiation, quasichemical changes such as depolymerization. Unlike metals, however, valence crystals have no conduction electrons. This permits them to retain electronic dislocations as well as atomic displacement. The trapping of dislocated electrons in the crystal by potential wells such as those created by atomic vacancies results in coloration of the normally transparent valence crystals. 

Here, Hhp = (Hq + kd ) and Hqc = (Cd ) represent dislocation-related dislocation hardening based on the H-P effect and bandgap-related hardening based on the quantum confinement effect, as indicated above, following Tse s [34] calculations. Ho is the single-crystal hardness and k is a material constant. C is a material-specific parameter equal to zero for metals and equal to 211Ny exp (1.191fi) for covalent materials, where Ne is the valence electron density and fj is the Philips ionicity of the chemical bond. 

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