Auger interatomic process

Excitation to the repulsive electronic state may also involve a multi-electron process. For example, creation of a core hole on a metal atom in an oxide may lead to an interatomic Auger transition which ultimately results in a positive oxygen ion which desorbs because it is now in a strongly repulsive Madelung well. Knotek and Feibelman have reported results which they interpret in this manner. Core ionization in the adsorbed molecule can also lead to an Auger process which leads to desorption. 

Interatomic Coulombic decay (ICD) is an electronic decay process that is particularly important for those inner-shell or inner-subshell vacancies that are not energetic enough to give rise to Auger decay. Typical examples include inner-valence-ionized states of rare gas atoms. In isolated systems, such vacancy states are bound to decay radiatively on the nanosecond timescale. A rather different scenario is realized whenever such a low-energy inner-shell-ionized species is let to interact with an environment, for example, in a cluster. In such a case, the existence of the doubly ionized states with positive charges residing on two different cluster units leads to an interatomic (or intermolecular) decay process in which the recombination part of the two-electron transition takes part on one unit, whereas the ionization occurs on another one. ICD [73-75] is mediated by electronic correlation between two atoms (or molecules). In clusters of various sizes and compositions, ICD occurs on the timescale from hundreds of femtoseconds [18] down to several femtoseconds [76-79]. 

The origin of the temperature-independent solid state broadening, 0.4 eV A <0.6 eV we attributed to spatial variations in the electronic contributions to the intramolecular relaxation energies in the vicinity of the surface (18, 19, 22). Similar widths (to 0.6 eV) have been observed in a variety of other contexts, including condensed thin films of and CO molecules ( ) and the sub-monolayer adsorption of these molecules on metal surfaces (29). Interatomic Auger and electron- hole shakeup processes have been proposed, but found to be too small to account for the observed widths in these cases (28, 48). On... 

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