Contour of the K-electron Compton line

An expression for the Compoton line contour near the maximum and the angular distribution of photons scattered by K-electrons is derived with a relative accuracy of the order of (αZ)2, inclusively. The wave functions of initial and final electrons in the Farry-Sommerfeld-Maue approximation and the Green function of the intermediate electron with one Coulomb correction have been used for calculating the corrections. The equivalence of the corrections of the (αZ)2 order to the Compton line contour and wave functions of electrons has been proved using the Feynman diagrams