The experimental dependence of the concentration of conduction electrons on the size of X-ray coherent scattering regions was obtained. The dependence was analyzed within the previously developed concentration model of the energy spectrum of samarium sulfide SmS. It was shown that the impurity donor levels in the SmS compound correspond to the samarium defect ions located at the boundaries of coherent scattering regions.

Defect Structure in SmS. L.N.Vasilev, V.V.Kaminskiĭ, M.V.Romanova, N.V.Sharenkova, A.V.Golubkov: Physics of the Solid State, 2006, 48[10], 1884-6