Coulomb Correction to Keldysh-Faisal-Reiss Theory for Photoionization of Atoms

In this paper, the Coulomb correction to Keldysh-Faisal-Reiss theory is derived in A-gauge. An application of the Coulomb correction to the photoelectric effect of H-atom is presented and the role of the gauge choice and the Coulomb correction are discussed. It is shown that the Coulomb correction plays an importaht role in the explanation of the recent energetic photoelectron spectra of He.