Linewidths and intensities of satellites in photoelectron spectra in the presence of an underlying continuum

The theory of lineshapes of satellites in photoelectron spectra in a simplified fourth-order perturbation theory is developed. The calculation of the monopole satellites of the 2p ionization of the neon atom has been carried out in second- and simplified fourth-order perturbation theory. The theoretical linewidths and the relative intensities of the satellites are in agreement with experimental photoelectron spectra taken at h nu =130.1 eV.