1sshake-up x-ray photoelectron spectrum of Na in NaCl and other Na salts

Shake-up lines associated with the ${\mathrm{Na}}^{+}$ [1s2p]3p atomiclike configurations in NaCl and several Na compounds have been identified in x-ray photoelectron spectra using commercial Al and Mg Kα sources. Two clearly separated peaks in a ratio of about 1:2 split by 4.4 eV and with a binding energy of 56.6 and 61.0 eV greater than that of the 1s peak are observed. The possibility to perform a similar shake-up spectroscopy on heavier third-period elements for atomic and condensed-matter studies is addressed.