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

The carbon 1 s photoelectron spectrum has been measured for CO2 at photon e nergies of 308, 320, and 330 eV with an instrumental resolution about half the natural linewidth. These spectra have been analyzed to obtain vibration al spacings, vibrational intensities, and the lifetime, tau, of the carbon 1 s core-hole state. Theoretical calculation of the lifetime width, (h) ove r 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 sm aller than that predicted for CH4 (96 meV). Experimental measurements indic ate, however, that the CO2 carbon 1 s width is, in fact, much larger than e xpected-99+/-2 meV-and is approximately the same as that found experimental ly for CH4 (95+/-2 meV). This result indicates that valence electrons on th e oxygen atoms may play a role in the Anger decay the carbon Is core hole i n CO2, and, hence, that a multicenter model may be necessary to describe th e Auger process.