ESDIAD Electron Stimulated Desorption Ion

ESDIAD Electron-stimulated desorption ion angular distribution [150-152] A LEED-like pattern of ejected ions is observed Orientation of adsorbed species... 

ESDIAD Electron-stimulated desorption ion angular distribution IPES Inverse photoemission spectroscopy... 

A diatomic molecule has to be adsorbed parallel to the surface in order to dissociate. The more favourable adsorption complex for molecules like CO on a group 8-10 metal surface is that in which the molecular axis stands perpendicular to the surface. It has been demonstrated by ESDIAD (electron stimulated desorption, ion angular dependence) that the molecular axis vibrates with regard to the surface normal and that the amplitude of vibration increases with increasing temperature this is shown in Fig. 4.41. 

ESDIAD Electron Stimulated Desorption Ion Angular Distribution... 

Madey and Netzer have examined the adsorption of HjO on Ni(lll) at 80 K, as well as the effect of preadsorbed oxygen, by ESDIAD (electron stimulated desorption ion angular distribution), TPD and LEED. At room temperature, water does not adsorb on Ni(lll). Water adsorbed on Ni(lll) at 80 K desorbs at 170 K (from the first monolayer) and 150 K (from an ice multilayer) without evidence for any decomposition products. For oxygen predosed Ni(lll) surfaces there is an extra peak at 275-300K in HjO TPD spectra, which is due to the interaction between water and adsorbed oxygen. The authors suggested the formation of OH above 120 K which recombined above 200 K to desorb as water and oxygen. Similar results have also been reported on Ni(110)5, Ni(100)5 and stepped Nidll). ... 

Acronyms ESDIAD (electron stimulated desorption ion angular distributions)... 

ESDIAD Electron Stimulated Desorption Ion Angular Distributions, 13 ETS Electron Transmission Spectroscopy ... 

Electron spin resonance (esr), 22 132 for lignin characterization, 15 10 Electron-stimulated desorption-ion angular distribution (ESDIAD), 24 74 Electron transfer (ET), 9 376-381, 388 mechanisms of, 13 444 rate constant for, 13 447 Electron-transfer dynamics, in... 

When adsorbed molecules are bombarded with electrons, local heating effects occur that lead to thermal desorption. In addition, there is a small but finite probability that electrons in the chemical bonds that hold the adsorbate to the surface will be excited into a repulsive state, leading to the desorption of that molecule either as a neutral species or as a molecular ion. Desorption of neutral species under electron-beam bombardment is frequently observed in studies of electron-surface interactions. A fraction of the adsorbed molecules will be ionized. These can be detected as positive ions, and the spatial distribution of this ion flux can be imaged on a fluorescent screen. Electron-stimulated desorption ion-angular distribution (ESDIAD) [56, 61, 64, 79-84] is the name of the technique that is used to learn about the site symmetry and orientation of adsorbed molecular species, since the molecular ions are usually emitted in the directions of their chemical bonds with the surface and with an unchanged orientation with respect to the orientation of the molecule when it was adsorbed on the surface. 

Electron beam impact can induce the desorption of molecules—neutral or ionized—in the direction of their chemical bond to the surface. The technique that takes advantage of this phenomenon to learn about surface bond directionality is called electron-stimulated desorption ion-angular distribution (ESDIAD) [56, 61, 64, 79-83]. Describe the bonding of a polyatomic molecule on a transition metal surface as determined by ESDIAD [112]. 

Fig. 7.1. Schematic diagram of the TOF-ESD microscopy system, termed the protoscope . A pencil-type electron gun for SEM and conventional low energy electron diffraction (LEED) gun for LEED, Auger electron spectroscopy (AES), and (electron stimulated desorption ion angular distribution (ESDIAD) are combined with an ion detector consisting of microchannel plates (MCPs) and a phosphor screen.

The nature of reaction products and also the orientation of adsorbed species can be studied by atomic beam methods such as electron-stimulated desorption (ESD) [49,30], photon-stimulated desoiption (PDS) [51], and ESD ion angular distribution ESDIAD [51-54]. (Note Fig. VIII-13). There are molecular beam scattering experiments such... 

Electron Stimulated Desorption (ESD) and ESD Ion Angular Distribution (ESDIAD)... 

---