Exciton broadening of the angle-resolved photoemission spectra of a semiconductor

Broadening of the angle-resolved photoemission spectra caused by the electron-hole attraction is considered. For the case of a semiconductor with the model parabolic dispersion law the spectral-line shape is found at arbitrary k_e and ?ω, the energy dependence of the spectrum width is presented too. For the real crystals of silicon, germanium, and grey tin the results of numerical calculations of these values are given in some points k_e. The accounting of the electron-hole interaction gives rise to shifts and widths up to 0.1 eV order of magnitude and results in an oscillating spectrum lineshape.