High-energy ion scattering spectroscopy

HEIS high-energy ion scattering/high-energy ion scattering spectroscopy... 

RBS, HEIS Rutherford Back Scattering, High Energy Ion Scattering (Spectroscopy)... 

Low Energy Ion Scattering Spectroscopy (LEISS) is a more recent development. Several studies in the Seventies showed that LEISS is highly surface-sensitive and can provide a useful addition to photoelectron spectroscopy (XPS). 

HEED = high energy electron diffraction IILE = ion-induced light emission INS = ion-neutralization spectroscopy IRS = infrared spectroscopy ISS = ion-scattering spectroscopy LEED = low energy electron diffraction LEIS = low energy ion scattering ... 

Techniques based on the interaction of ions with solids, such as secondary ion mass spectrometry (SIMS) and low-energy ion scattering (LEIS) have undoubtedly been accepted in catalyst characterization, but are by no means as widely applied as for example X-ray photoelectron spectroscopy (XPS) or X-ray diffraction (XRD). Nevertheless, SIMS, with its unsurpassed sensitivity for many elements, may yield unique information on whether or not elements on a surface are in contact with each other. LEIS is a surface technique with true outer layer sensitivity, and is highly useful for determining to what extent a support is covered by the catalytic material. Rutherford backscattering (RBS) is less suitable for studying catalysts, but is indispensable for determining concentrations in model systems, where the catalytically active material is present in monolayer (ML)-like quantities on the surface of a flat model support. 

Surface analytical methods — Important ex situ methods for surface analysis are X-Ray Photoelectron Spectroscopy (XPS) UV-Photoelectron Spectroscopy (UPS), Auger Electron Spectroscopy (AES), Ion Scattering Spectroscopy (ISS), Rutherford Backscattering (RBS), Secondary Ion Mass Spectroscopy (SIMS), Scanning Electron Microscopy (SEM), Electron Microprobe Analysis (EMA), Low Energy Electron Diffraction (LEED), and High Energy Electron Diffraction (RHEED). 

In the case of alloy electrocatalysts, the identification of the alloy constituent (at the topmost layers) during the electrocatalytic reaction is rather difficult. Therefore, the assumption of stability after the reaction makes the study rather simpler. In this case, the UHV conditions can be applied only in the ex situ variation, and then an idea of the process mechanism is also required. Not many techniques can be used for the identification of the alloy constituents. However, techniques under a high vacuum condition are applied x-ray photoelectron spectroscopy (XPS), Auger spectroscopy, low-energy ion scattering, and low-energy electron diffraction. 

Fig. 1. Experimental techniques available for surface studies. SEM = Scanning electron microscopy (all modes) AES = Auger electron spectroscopy LEED = low energy electron diffraction RHEED = reflection high energy electron diffraction ESD = electron stimulated desorption X(U)PS = X-ray (UV) photoelectron spectroscopy ELS = electron loss spectroscopy RBS = Rutherford back scattering LEIS = low energy ion scattering SIMS = secondary ion mass spectrometry INS = ion neutralization spectroscopy.

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