โ Scribed by E.T. Jensen; R.E. Palmer; P.J. Rous
No coin nor oath required. For personal study only.
A high-resolution electron-energy-loss spectroscopic study of Ox monolayers physisorbed on graphite (in the Q-phase) reveals a resonance in the cross section for the X 2; -+a '4 electronic excitation of O2 at an electron beam energy of 8 eV, and is attributed to the formation of a temporary negative ion. Measurements of the angular dependence of the inelastically scattered electrons, in conjunction with multiple electron-scattering calculations, show that the intermediate state has dx symmetry, consistent with the 'II, resonance observed in gas-phase electron-scattering studies. The angular distributions also provide evidence for dynamical molecular tilting of the molecular axis about its equilibrium position in both the yZ-and S-phases of O2 on graphite.
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We report the photon stimulated desorption of O-ions from thin films ( 1-10 monolayers ) of 02 condensed on graphite in the photon energy range 15-35 eV. The negative ion yield exhibits two peaks, at 25 and 30 eV, quite unlike the gas phase photodissociation cross section. Our results indicate that
We have investigated the production of O-, 02 and 01 ions by electron-stimulated desorption from well-ordered films of physisorbed O2 on graphite. Resonances observed in the yield ofall products as a function ofelectron impact energy are attributed to dissociative electron attachment, generating O-i