AbstractThe electronic and optical properties of monoclinic and rhombohedral V2O3 are investigated in the framework of density functional theory (DFT) and GGA+U. It is found that, the metal-insulator transition (MIT) in V2O3 is induced by the on-site correlation effect, accompanied with a distinct orbital occupation change. The MIT is independent of the structural transition. The theoretical energy gap 0.6 eV agrees with the experimental value of 0.66±0.05 eV very well. Subsequently, the optical properties are also investigated. Interestingly, the insulating V2O3 shows minimal absorption in the infrared region, but the metallic V2O3 becomes opaque in such region. Therefore, a threshold at about 1 eV interprets the experimental charge gap (Perucchi et al., 2009) theoretically. Such infrared thermochromism makes it a potential candidate for several optical applications.