Density Functional Theory (DFT) Study of LaMn _0.4 Fe _0.6 O ₃ Perovskite Oxide

Abstract The perovskite molecule was studied with density functional theory (DFT) using different calculation method/basis sets; RB3LYP/GENECP; PBEPBE /GENECP, and PBEPBE/SDD in the Gaussian 09 program. The most stable 3D structure of the molecule was optimized. Based on the structure of this optimized molecule; the geometric properties; Mullikan charges; dipole moment; polarizability was calculated. Also; the theoretical vibration frequency values were compared with the experimental data. HOMO‐LUMO energies were used to determine the electronic properties such as electron affinity (EA); ionization potential (IP); electronegativity (χ); chemical hardness and softness. Thermodynamic properties thermal energy; thermal capacity; entropy was calculated. Molecular electrostatic potential (MESP) was determined 2.5 × 10 −2 eV; 2.7 × 10 −2 eV, and 3.6 × 10 −2 and band gap values; 1 eV; 0.012 eV; 0.016 eV was observed in RB3LYP/GENECP; PBEPBE /GENECP, and PBEPBE/SDD basis sets. Total density of states (TDOS) plots were visualized by GaussSum software which represents the virtual and occupied orbitals