Carbon 1s core-hole lifetime in CO2 -: art. no. 042503

The carbon 1 s photoelectron spectrum has been measured for CO2 at photon energies of 308, 320, and 330 eV with an instrumental resolution about half the natural linewidth. These spectra have been analyzed to obtain vibrational spacings, vibrational intensities, and the lifetime, tau, of the carbon 1 s core-hole state. Theoretical calculation of the lifetime width, (h) over bar h/tau, using a one-center model, which assumes that only the valence electrons localized on the atom with the core hole can participate in Auger deexcitation of the cure hole, predicts a value of 66 meV, considerably smaller than that predicted for CH4 (96 meV). Experimental measurements indicate, however, that the CO2 carbon 1 s width is, in fact, much larger than expected-99+/-2 meV-and is approximately the same as that found experimentally for CH4 (95+/-2 meV). This result indicates that valence electrons on the oxygen atoms may play a role in the Anger decay the carbon Is core hole in CO2, and, hence, that a multicenter model may be necessary to describe the Auger process.