Energy level bending and alignment at the interface between Ca and a phenylene vinylene oligomer

We have studied the interface formation of a vinylene phenylene oligomer with a Ca substrate using photoemission spectroscopy. The evolution of core and valence spectra during the deposition of the oligomer on Ca has indicated the molecular energy level bending. The total energy level bending was 0.5 eV and the thickness of the level bending region was about 100 Å. We propose an energy level diagram of the oligomer-Ca interface based on the information obtained from the photoemission spectra.