Electron Capture and Loss Processes in the Interaction of Hydrogen, Oxygen, and Fluorine Atoms and Negative Ions with a MgO(100) Surface

Ustaze, S.; Verucchi, Roberto; Lacombe, S.; Guillemot, L.; Esaulov, V.A.

doi:10.1103/physrevlett.79.3526

Cited by 69 publications

(58 citation statements)

References 24 publications

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“…This as well as appearance of quantized states, due to confinement [5], would obviously affect electron capture and loss probabilities; capture or loss would, e.g., be inhibited in the bandgap region, and the description of it would need to be different. In the case of discrete states, non-resonant velocity-dependent charge transfer processes [29][30][31] may play a role as for dielectric surfaces and should be treated using a molecular description, as this has been done also for ionic solids [32,33]. Finally, it has also been suggested [14] that perhaps defect sites on the cluster or interaction with adatoms, atoms at kinks, and boundaries may somehow play a role.…”

Section: Resultsmentioning

confidence: 99%

Electron transfer processes on Au nanoclusters supported on graphite

et al. 2013

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Electron transfer processes play an important role in surface chemistry. This paper presents results of a study of changes in resonant electron transfer processes, as a function of gold cluster sizes, on the example of electron transfer between Li + ions scattered on Au clusters on highly oriented pyrolytic graphite (HOPG). The gold nanoclusters were grown on lightly sputtered HOPG surface in order to obtain a wide coverage distribution of clusters. The growth of clusters was monitored by scanning tunneling microscopy. We found that electron transfer is much more probable on small clusters, whose lateral size is of the order of 2 to 3 nm and height in the 1-nm range, than on bulk Au or thin Au films. A comparison with Au clusters grown on the semiconducting titania did not reveal significant differences with HOPG.

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Section: Resultsmentioning

confidence: 99%

Electron transfer processes on Au nanoclusters supported on graphite

et al. 2013

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“…But it has been found that for ionic crystals such as, for instance, LiF, charge exchange proceeds via capture of electrons from the anionic sites of the surface in a binary ion-atom interaction. [42][43][44] And once the negative ion is formed it cannot be destroyed by resonant electron loss ͑as in the case of metals͒ because of the band gap of the ionic crystal. It is safe to expect a similar behavior here.…”

Section: Discussionmentioning

confidence: 99%

Effect of long duration UV irradiation on diamondlike carbon surfaces in the presence of a hydrocarbon gaseous atmosphere

Riedo

Wahlström

Scheer

et al. 2010

Journal of Applied Physics

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Measurements of the effect of long duration UV irradiation (up to 2905 min) of flight quality diamondlike carbon charge state conversion surfaces for application in space research in the presence of a hydrocarbon atmosphere were done. An isopropanol atmosphere was used for simulating the hydrocarbon gaseous environment for an instrument on a satellite in space. Charge state conversion surfaces are used in neutral particle sensing instruments where neutral atoms have to be ionized prior to the analysis. A narrow-band (126±5 nm) discharge lamp and a broad-band deuterium lamp (112–370 nm) were used as sources of UV radiation. The UV irradiation of a surface results in the desorption of some volatiles present on the surface and the decomposition of others. Desorption of volatiles, mostly water, is observed for both UV sources. The decomposition of the hydrocarbons and the subsequent build-up of a hydrocarbonaceous layer is only observed for the broad-band UV lamp, which is more representative for the space environment. Unfortunately, the hydrocarbonaceous layer cannot be removed thermally, i.e., it is permanent, and causes a degradation of the performance of the charge state conversion surfaces. With the present measurements we can quantify the UV influence at which the degradation of the conversion surfaces becomes noticeable.

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“…The ion fraction was found to be large: 80% at 1 keV. A description of electron transfer for MgO can be found in the original papers [44][45][46][47][48][49][50]. We recall briefly that in the case of MgO, when the F atom approaches a lattice O atom (O dÀ negative ion site; d is of the order of 2) the F À level (electron affinity = 3.4 eV) is shifted closer into resonance with the deep lying O(2p) related levels (about 8 eV below vacuum level) because of the effect of the Madelung potential, induced by the surrounding positive charges.…”

Section: Negative Ion Fractionsmentioning

confidence: 99%

“…This is not the case of dielectric surfaces where significantly fewer studies have been performed [44]. Recent years have witnessed a considerable activity centred on wide band gap ionic insulator surfaces like MgO and alkali halides; experimental and theoretical work [45][46][47][48] performed has led to a fairly good understanding of the specific mechanisms that govern the charge transfer dynamics that is quite distinct from that of metals. In the case of metals charge transfer is generally described in a delocalised, jellium model type, free electron description of the solid .…”

Section: Introductionmentioning

confidence: 99%