Two-photon knocking-out of two electrons of the 1s2-shell of the neon atom

The absolute values and shape of the cross section for the process of two-electron excitation/ionization of the 1s2-shell of the 10 Ne atom by two linearly polarized photons are calculated using second-order quantum mechanical perturbation theory. The many-particle effects of relaxation of the atomic residue in the field of creating virtual vacancies and the decay of vacancies via Auger and/or radiative channels are taken into account. It is shown that the probability of the process of two-photon absorption by the deep 1s2-shell accompanied by the creation of double 1s-vacancies essentially predominates over the probability of the process of two-photon one-electron excitation/ionization of the 1s2-shell in the range of x-ray photon energies (h/2π)/ω≥ 930 eV. (author). Letter-to-the-editor