Calculation of electronic and optical properties of Na2S in the orthorombic phase

In this paper, the electronic and optical properties of Na2S in orthorhombic structural phase have been investigated. Calculations have been performed by using wien2k package which is based on density functional theory and FP-LAPW method. From the calculated band structure, band gap is about 2.405eV. In valence band S atoms mostly contributed and in conduction band Na atoms. The optical properties resulting are including the dielectric function, refractive index, extinction coefficient, absorption coefficient and Energy Loss function.According to the obtained results that indicate the maximum amount contribution imaginary dielectric function absorption and extinctions for energy absorption occurs and the maximum 5.5 eV and the maximum value of the real part dielectric function that indicates the maximum reflectance and energy refractive is observed near 5.4 eV. The results are good agreement with other available data.