COMPARISON OF PHOTOELECTRON SPECTRA OF ${\rm Cu}_n^-$, ${\rm Ag}_n^-$, AND ${\rm Na}_n^-$: MOLECULAR ORBITALS VERSUS ELECTRONIC SHELLS

The photoelectron spectra of [Formula: see text] clusters are compared to the results of quantmn-chemical ab-initio calculations (n=2-9) and to the predictions of the shell model. The shell model yields qualitative assignments of the dominant features in the spectra to photoemission from occupied electronic shells. These correspond to the exact quantitative assignments to transitions into various electronic states of the neutral clusters according to the quantum-chemical calculations. The photoelectron spectra of [Formula: see text] and [Formula: see text] clusters exhibit certain similarities to the Ag data in agreement with the basic idea of the shell model.