Near threshold excitation of K V V Auger spectra in carbon monoxide using electron–electron coincidence spectroscopy

Electron–electron coincidence spectroscopy has been used to separate KVV Auger spectra in CO into several component spectra, each arising from different core-excited initial states. Results are presented for the Auger decay of ions in which either a carbon 1s or oxygen 1s electron has been ionized and for the decay of neutral molecules in which either a carbon 1s or oxygen 1s electron has been excited to the vacant 2π orbital. The spectra from the neutral molecules have been studied and analyzed in some detail. These autoionization spectra can be broken into two parts. The highest kinetic energy part where the 2π electron participates in the decay is easily understood; in this case, the Auger transitions lead to well-known one-hole states of CO+. The lower-energy part arises from deexcitation with the 2π electron remaining as a spectator. This part of the spectrum is similar to the ‘‘normal’’ Auger spectrum shifted approximately 10 eV by the Coulomb interaction with the spectator electron. The similarity is greatest for the Auger spectra of CO but is less apparent for the spectrum of N2.