NewKαsatellites in the electron-excited x-ray emission spectrum ofFe26

A 40-cm curved muscovite mica crystal spectrograph of the transmission (Cauchois) type has been used to identify six new high-frequency $K\alpha$ satellites of Fe at 1.9230, 1.9176, 1.9062, 1.8939, 1.8810, and 1.8698 Å by means of electron excitation. The first four satellites have been assigned to transitions ${\mathrm{}\left(1s\right)\mathrm{}}^{-1\mathrm{}}{\mathrm{}\left(2p\right)\mathrm{}}^{-n}\to {\mathrm{}\left(2p\right)\mathrm{}}^{-n-1\mathrm{}}$, for $n=2-5\mathrm{}$. Relativistic Dirac-Fock (RDF) calculations for the energies of initial and final configurations give excellent agreement with the experimentally observed energies. However, the last two lines have been only tentatively assigned to transitions ${\mathrm{}\left(1s\right)\mathrm{}}^{-1\mathrm{}}{\mathrm{}\left(2s\right)\mathrm{}}^{-n}{\mathrm{}\left(2p\right)\mathrm{}}^{-5\mathrm{}}\to {\mathrm{}\left(2s\right)\mathrm{}}^{-n}{\mathrm{}\left(2p\right)\mathrm{}}^{-6\mathrm{}}$, for $n=1\mathrm{} \mathrm{and} 2$ because RDF calculations for these configurations were were not available. This is the first time that more than two vacancies have been observed following electron bombardment of a target with $Z>\mathrm{}19\mathrm{}$. The possibility of such multiple ionization has already been predicted by the well-known shake-off theory. Previously reported results for high-frequency Fe $K\alpha$ satellites have also been recorded. By using the theoretically calculated energies given by Gianturco, the components of the transition $K^{-1\mathrm{}}{L}^{-1\mathrm{}}\to L^{-2\mathrm{}}$ assigned by Ramberg and Kennard to these satellites under a pure $L-S$ coupling scheme have been confirmed. The satellite ${{\alpha }_3}^{\prime \prime }$, which does not form a component of the earlier group, has been assigned for the first time to the transition ${}_{}{}^3{}_{}{}^{}P_{1,2}^{}{}_{}{}^{}\to {}_{}{}^1{}_{}{}^{}D_2^{}{}_{}{}^{}$ allowed in the intermediate-coupling scheme.