Nuclear excitation by electron transition near the <Emphasis Type="Italic">K</Emphasis>-shell ionization threshold of an atom

A model of nuclear excitation by electron transition near the K-shell ionization threshold of an atom is proposed. The nuclear excitation cross sections have been calculated for ¹⁹⁷Au, ¹⁹³Ir, and ¹⁸⁹Os as functions of the energy of the photons ionizing the atomic shell. It is shown that excitation of ¹⁸⁹Os begins under the K-shell photoionization threshold of Os, while excitation of ¹⁹⁷Au and ¹⁹³Ir begins above the K-shell photoionization threshold of Au and Ir, respectively.