Deep understanding of different luminescence phenomena in materials, in additions to modern experimental analysis, requires accurate and reliable theoretical studies. In this thesis, SrS crystal doped with Ce impurity is our target material for theoretical description of the luminescence phenomena. In this regard, density functional computations by using full potential LAPW technique are employed as powerful and reliable computational tools. In addition, experimental measurements by external collaborators are used for comparison. At the first step, possible configurations of the doped crystal are addressed in the framework of first-principles thermodynamics and substitution of Sr atom by Ce impurity is argued to be the most stable configuration of the doped SrS, compatible with experimental observations. After calculating electronic structure of a group of semiconducting compound within different exchange-correlation functionals and comparing the resulting band gaps with experiment, we introduce the ex-TB-mBJ method for more reliable calculation of electronic structure of correlated systems containing d electrons. Then, electronic properties of the stable configuration of Ce doped SrS is investigated and the metallic behavior of this system is shown. It is argued that neither the Hubbard correction scheme nor changing the spin configuration of the system is able to resolve this elaborate problem. Moreover, following some experimental signals, effect of core level ionization of the impurity in the electronic properties of the system is investigated and performance of this method in correct description of the luminescence properties of the doped crystal is discussed. Finally, effect of Sr vacancy in the Ce doped SrS is investigated and it is observed that this system provide very good description for the observed luminescence properties of Ce doped SrS.