Valence electronic structure of ruthenium based complexes probed by photoelectron spectroscopy at high kinetic energy (HIKE) and modeled by DFT calculations

The valence electronic structure of a series of molecular films containing ruthenium polypyridine complexes has been investigated by photoelectron spectroscopy (PES) at high kinetic energy (HIKE) using hard X-ray. The experiment shows the possibility to experimentally probe the metal contribution to the valence spectra in a bulk sensitive mode. Specifically to directly follow the Ru 4d contribution to the highest occupied molecular orbitals of such complexes. The experimental spectra are accurately modeled by DFT calculations only if a crystal structure environment is taken into account showing the importance of intermolecular interaction for modeling the electronic structure of such complexes.