Our calculations were done with the help of density functional theory (DFT) and use the generalized gra-dient approximation (GGA), The pseudo-potential linearised augmented plane wave (PP-LAPW) method is applied to solve the Kuhn-Sham equations, in order to search for the structural, electronic and optical properties of the FeNi3 original alloy, as well as the FeNi2Mo and FeNi2Nd alloys resulting from doping with (Mo, Nd) atoms in the original cell. The lattice parameters of the alloys were calculated and compared with previous theoretical and experimental results, the electronic properties such as energy bands and the total density of states showed the metallic property of the alloys and that the FeNi2Nd alloy has more magnetic moment. Also it was found that the contribution of the 3-d orbital is dominant, and this appears by comparing the density of partial states recorded in the two alloys, and this affects the electronic and magnetic properties of the two alloys. The general results of optical properties including absorption coefficient, refractive index, optical conductivity of FeNi2Mo and FeNi2Nd are discussed and compared with each other, our results show new and important optical properties.

DFT, Siesta, Alloys, Properties structural, Properties Optic.