Prediction study of structural, electronic and optical properties of 4C₁₆H₁₀Br₂O₂ Bis (m-bromobenzoyl) methane crystals

By first-principles calculations with density functional theory and a pseudopotential approach, the structural, electronic, and optical properties of the anhydrous 4C₁₆H₁₀Br₂O₂ Bis (2-Bromobenzoyl) Methane crystals in Pbnc (N°60) and P2₁/c (N°14) space group are investigated. All computations are determined by a generalized gradient approximation, local density approximation and an ultra-soft pseudopotential. The calculated equilibrium parameters are in good agreement with their available experimental data. This calculation shows that the GGA/PW91 functional overestimate the lattice constant, unlike the LDA/CA-PZ. The Br–C bond distance of 1.856 (1.902) Å is comparable with experimental value of 1.901 (1.896) Å in Pbnc (P2₁/c) space groups. The direct band gap nature is obtained for both space groups Pbnc and P2₁/c, since the maximum of the valence band and the minimum of the conduction band are both situated at the YA center.