Use of two-dimensional photoelectron spectroscopy in the decomposition of an inner-shell excitation spectrum broadened by super-Coster-Kronig decay

The Ge 3p core excitation spectrum of the n-butylgermane molecule only reveals two peaks, whereas the rest of the fine structure is obscured due to the large lifetime broadenings of core-excited states. A two-dimensional presentation of resonant photoemission spectra allows us to observe some other resonances. The interpretation of experimental results is supported by ab initio calculations conducted at the four-component relativistic level of theory with full account made for spin-orbit interactions already in the zeroth-order Hamiltonian.