energy levels / toelectron energy / excess photon energy / pulsed-field ionization zero-kinetic-energy photoelectron / higher energy / hemispherical energy berg / e- innershell / zero-energy electron / photon energy / electron energy analyzers / energy level diagram / kinetic energy / e- 4d / e - 4d / energy distribution / wide energy range / low-energy side / zero energy cess / energy / /