Doubly excited states of molecular hydrogen as studied by coincident electron-energy-loss spectroscopy

The doubly excited states of molecular hydrogen have been studied by means of electron-energy-loss spectroscopy in coincidence with the detection of H(2p) formation at 80 eV incident energy and scattering angle. This is the first observation of doubly excited states of in electron energy-loss spectra. It is shown that a forbidden doubly excited state makes a large contribution as well as allowed states. The measured spectrum has been analysed by theoretical fits based on the reflection approximation.