Strong interatomic effects accompanying core ionization of atomic clusters

Fourth-order Green’s function calculations have revealed many interesting features in the core-level spectra of Be_n and Mg_n (n=2,3,4) clusters. The most striking of them are unusually low-lying intense satellites. These are absent in the respective atomic spectra and not observed in the spectra of typical molecules. An analysis in terms of localized configurations attributes these satellites to distinct interatomic processes. These processes comprise charge and energy transfer from one atom to neighboring atoms. The spectra are sensitive to the size and conformation of the clusters. This can be useful for the experimental identification of the clusters. The emerging physical picture of core ionization of small soft metal Be_n and Mg_n clusters is quite general and applicable to other weekly bound atomic and molecular clusters.