Direction-dependent initial-state relaxation in oxygenKx-ray emission

High-resolution oxygen K x-ray spectra have been obtained from a number of ionic insulators. A distortion of the 1$s^{\mathrm{-}1?}$(${\mathrm{hyV}}^{\mathrm{-}1}$ x-ray emission band due to the initial 1s hole is observed and related to the variation in the 1$s^{\mathrm{-}1}$ $V^{\mathrm{-}1?}$(${\mathrm{hyV}}^{\mathrm{-}2}$ satellite structure as a function of the bonding character. A shake model which considers the influence of the crystal environment on the relaxation of the ${\mathrm{O}}^{2\mathrm{-}}$ 2p orbitals is shown to account for the diminution of the satellite intensity with increasing covalency.