On the local density approximation for Breit interaction

The large relative error of the local density approximation for the transverse-photon-electron or Breit energy in atoms and solids is shown to arise from spurious self-interaction of the 1s electrons. Orbital self-interaction correction dramatically reduces this error. On the other hand, the large relative error of the local density approximation for the Breit contribution to the 2s electron removal energy is almost unchanged by self-interaction correction.