Resonant behavior of satellite photoelectrons in the Ni 3p and 3s region at the Ni 2p excitation of K2Ni(CN)4

Resonant Ni 3p and 3s photoelectron spectra were measured at the Ni 2p edge for anhydrous K2Ni(CN)4 complex. A number of satellite series, which are mostly forbidden in the non-resonant spectrum, become strongly observable via the resonant excitations. Each satellite lowers its kinetic energy for the higher resonance energy, showing a one-to-one correspondence with the Ni 2p3/2 and 2p1/2 resonantly excited states. This behavior manifests a one-electron feature in the core excitons, where electrons are bound by the singly and doubly charged states in the intermediate and final states, respectively, and is characteristic of molecular systems in solids such as Ni(CN)42−.