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Reflection (e,2e) experiments from surfaces RID G-7348-2011
No full textThe application of electron-electron coincidence experiments (e,2e) to solid samples, although begun in the earliest stages of the development of such a spectroscopy, has been extensively exploited only during the past few years and the applicability to surfaces has just started to be pursued. The feasibility of (e,?e) experiments in grazing angle reflection geometry has been recently established for the first time. In spite of the success, the possibility of using the grazing angle (e,2e) technique as a binding energy and (or) momentum spectroscopy of surface states rests on the accurate knowledge of the ionization mechanism. To understand which is the dominant process responsible for the reflection (e,2e) events, under various energies and kinematical conditions, is still an open problem. Two possible mechanisms are envisaged that can generate pairs of correlated electrons in the reflection geometry: a single inelastic collision at large momentum transfer or a double collision (elastic and inelastic) at high and low momentum transfer, respectively. in the present paper are reviewed the results of recent (e,2e) experiments performed at energies from threshold up to 300 eV and with kinematics from normal to grazing incidence. They allow elucidation of the (e,2e) ionization mechanism on surfaces at both grazing and normal impact
The behavior of extreme air temperatures in Rome during the last hundred years and hypothetical explanation based on atmosferic pollution
No full textElectron-electron coincidences experiments on surfaces, status and perspective of a new spectroscopy RID G-7348-2011
No full textThe past decade has witnessed a sizeable increase of activity in the field of electron-electron coincidence on surfaces. Electron collision and photon absorption have been exploited to perform correlated experiments in a variety of kinematics and involving valence as well as core electrons. In these break-up experiments the kinematics of the ionising event is fully determined. In this talk I shall concentrate on those experiments performed in reflection geometry as they are thought to be particularly suited to investigate surface rather than bulk properties. To understand which is the dominant mechanism that leads to ejection of pairs of electron from the surface and what novel information is yielded by these spectroscopies is the main aim of this work. This issue will be discussed in two cases : a) the grazing and normal incidence (e,2e) experiments performed at low and intermediate energies, b) the first angle resolved Auger-photoelectron coincidence experiment. It will he shown that for both classes of experiments, depending on the kinematics chosen, the correlated behaviour of the pairs of electrons detected might prevail on the independent particle one
Many particle spectroscopy of atoms, molecules, clusters and surfaces
No full textSelected papers from the International Conference on Many particle spectroscopy of atoms, molecules, clusters and surfaces, 22-24 June 2006, Rome, Ital
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