B3LYP investigation of response properties of alkali halides on external static electric fields

► All electron B3LYP calculated structural, dielectric, and optical properties of first six alkali halides. ► Effect of external electric field on electronic and structural properties of alkali halides. ► Explanation of band widening and band-gap reduction in the presence of external electric field. ► Dielectric strengths calculated using von Hippel's low-energy criterion and Callen's equation.