Inverse photoemission

We review the experimental apparatus presently available for use in inverse photoemission spectroscopy (IPES) in the vacuum ultraviolet (5–30 eV) energy range. We consider the design and use of different photon detectors including the gas-filled Geiger Muller counters and the more recent solid-state isochromat detectors. We review the properties of various tunable photon detectors employing either gratings or lenses as the dispersive element. Detection of the polarization of the photons and its role in the emission process is also discussed. A survey of the different electron gun designs is presented with a discussion of the limitations imposed by space-charge effects on both the available current and the achievable momentum resolution. Finally we present a brief review of spin-polarized IPES (SPIPES) and discuss the introduction of spin polarization in the incident electron beam.