Separation of one- and many-electron effects in the excitation spectra of3dimpurities in semiconductors

We present a new multiplet theory that separates mean-field from multiplet effects in the excitation and donor-acceptor ionization spectra of localized impurities. Analysis of the experimental data for all $3d$ impurities in ZnO, ZnS, ZnSe, and GaP for which sufficient data exist and for the bulk Mott insulators CoO, MnO, and NiO reveals, for the first time, regular chemical trends in many-electron effects with the impurity and the host-crystal covalency and delineates the regime where one-electron theory is applicable from the region where it is not.