Correlation between optical electronegativity and refractive index of ternary chalcopyrites, semiconductors, insulators, oxides and alkali halides

Interesting relationships have been found between energy gap, optical electronegativity and refractive index for different materials viz. elemental compounds, binary and ternary chalcopyrites, semiconductors, insulators, oxides and alkali halides. An excellent agreement has been obtained from modified Herve and Vandamme relation and the literature values. It can be observed that as the optical electronegativity (Δχ∗) values for the group of semiconductors with the common cation decreases, their refractive index increases. Compounds with covalent nature like AlSb and ZnS have small magnitude of optical electronegativity (Δχ∗) and relatively high refractive index. The trend is quite reverse in the case of ionic molecules. This work highlights the significance of the interrelation between energy gap, optical electronegativity and refractive index.