Carbon dioxide ion dissociations after inner shell excitation and ionization: the origin of site-specific effects.

Multi-coincidence experiments with detection of both electrons and ions from decay of core-excited and core-ionized states of CO2 confirm that O2(+) is formed specifically in Auger decay from the C1s-π* and O1s-π* resonances. Molecular rearrangement occurs by bending in the resonant states, and O2(+) is produced by both single and double Auger decay. It is suggested that electron capture by C(+) after partial dissociation in the doubly ionized core of excited CO2(+), formed by shake-up in spectator resonant Auger decay, accounts for high kinetic energy and high internal energy in some C + O2(+) fragments.