Emission of γ rays by x-ray electron-nuclear transitions

We estimate the cross section of processes in which a transition effected by an inner atomic electron takes place simultaneously with a nuclear electromagnetic transition, for electric and magnetic interactions of various multipole orders. We calculate the rate of deexcitation of isomeric nuclei induced by processes of this type for the case when the holes in the atomic shells are produced by incident ionizing electrons and find that the induced nuclear deexcitation rate becomes comparable to the natural decay rate for ionizing fluxes of the order of ${10}^{14}$ W cm${}^{-2}$. We show that for $E1\mathrm{}$ and $M1\mathrm{}$ nuclear processes for which there is a matching between the electron and the nuclear transition energies, these electron-nuclear transitions can be used to produce pulses of Mössbauer radiation, with yields of the order of ${10}^4$ Bq mA${}^{-1}$.