Perturbation effects of electron screening on wave functions and dipole matrix elements of $K$ and $L$ electrons of ions or inner shells of atoms have been computed to order $Z^{-1\mathrm{}}$. Some screening effects of this order have also been computed for the $M$ shell. Some of the terms of order $Z^{-2\mathrm{}}$ have also been evaluated and found to be small compared with those neglected in this paper. The dipole matrix elements have been used to compute x-ray mass absorption coefficients and the comparison with the experimental values is discussed.

• Received 9 February 1954

DOI:https://doi.org/10.1103/PhysRev.95.72