Accurate separation of X-ray α₁–α₂ doublets by the `substitution method'

An improved `substitution method' for the separation of X-ray diffraction α₁−α₂ doublets is based on the possibility of refining both the proportionality constant between the α₁ and α₂ contributions to the line intensity and the doublet separation expressed in terms of the diffraction angle or of a related variable in the reciprocal space. Optimization of these two parameters, with a proper evaluation of the error, clearly shows the statistical nature of the oscillations appearing on the high-angle side of the pure α₁ component after correction; their elimination by polynomial smoothing can therefore be performed and a procedure is suggested for achieving this result. A computer program, based on these principles, has been written and tested in many practical cases.