We have measured high-resolution electron decay-in-flight spectra of highly excited carbon ions, produced by 2-MeV ${\mathrm{C}}^{+}$ beams emerging from carbon foils. An almost complete identification for the resolved spectral lines is suggested for the prompt and time-delayed electron emission spectra. To assign the observed structures excitation energies for various core-excited states have been calculated using the generalized Brillouin theorem-multiconfiguration method of Schwarz and Chang. Experimental term energies for Coulomb and metastable autoionizing states in two-, three-, and four-electron carbon ions are tabulated and compared to calculated transition energies. Because of line blending most of the experimentally deduced term energies are uncertain to ±0.4%. Some spectral features in the high-energy portion of the prompt spectrum can be attributed to decays of doubly excited He-like carbon ions.

• Received 16 August 1976

DOI:https://doi.org/10.1103/PhysRevA.15.926