Journal ArticleDOI
Reflection and Dissociation of H2 on Tungsten
Joe N. Smith,Wade L. Fite +1 more
TLDR
In this paper, the angular distribution of reflected H2 displays a shift toward the specular ray, and the sticking probability of H2 on tungsten approaches a limiting value of 0.3.Abstract:
Through the use of modulated atomic beam techniques, the reflection and dissociation of H2 at a tungsten surface above 2500°K has been studied. Two experimental configurations were employed. In the first configuration, a collimated beam of molecular hydrogen was directed at the tungsten surface, and the angular distribution of particles evaporating from the surface was examined mass spectrometrically. In the second configuration, the tungsten test surface was located in the first of three differentially pumped vacuum chambers. H2 was admitted into this chamber, thereby providing an isotropic source of incident particles. Particles evaporating from the surface were collimated and examined mass spectrometrically in the third chamber. From these experiments it is observed that at high temperatures the angular distribution of atomic hydrogen evaporating from the target surface obeys the cosine law. However, the angular distribution of reflected H2 displays a shift toward the specular ray. Above 2500°K the sticking probability of H2 on tungsten approaches a limiting value of 0.3.read more
Citations
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Journal ArticleDOI
Hydrogen desorption from the monohydride phase on Si(100)
Kumar Sinniah,Michael G. Sherman,Lisa B. Lewis,W. Henry Weinberg,John T. Yates,Kenneth C. Janda +5 more
TL;DR: In this paper, it was shown that the rate limiting step of the reaction is the promotion of a hydrogen atom from a localized bonding site to a delocalized band state, which then reacts with a localized atom to produce molecular hydrogen which desorbs.
Journal ArticleDOI
Adsorption of atomic hydrogen on clean cleaved silicon (111)
G. Schulze,Martin Henzler +1 more
TL;DR: In this paper, the combination of different experimental methods showed that the hydrogen affects more than just saturation of dangling bonds and showed that at low coverage the desorption kinetics of state β1 is of second order with activation energy Ed= 2.5eV± 0.1eV.
Journal ArticleDOI
Hydrogen chemisorption and the structure of the diamond C(100)-(2 × 1) surface
TL;DR: In this paper, the surface reconstruction of a diamond C(100)-(1 × 1) surface was investigated and the presence of chemisorbed hydrogen on the surface was monitored by electron-stimulated desorption time-of-flight spectroscopy (ESD-TOF).
Journal ArticleDOI
Desorption kinetics of hydrogen and deuterium from Si(111) 7×7 studied using laser‐induced thermal desorption
TL;DR: In this article, the desorption of hydrogen and deuterium from Si(111) 7×7 was studied using laser-induced thermal Desorption (LITD) and temperature-programmed desorptions (TPD) mass spectrometry.
Journal ArticleDOI
Production of high-quality amorphous silicon films by evaporative silane surface decomposition
TL;DR: In this paper, a simplified model for the deposition process is suggested based on this data and other information, and a novel substrate holder is used to control the growth of a•Si:H growth on nearby substrates.
References
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Journal ArticleDOI
Collisions of Electrons with Hydrogen Atoms. I. Ionization
Wade L. Fite,R. T. Brackmann +1 more
TL;DR: In this article, the cross section for ionization of the hydrogen atom on electron impact has been measured as a function of electron energy, and the absolute atomic cross sections, determined by multiplying this ratio by the known molecular cross-sections, are cross-checked by taking relative cross sections for the atom.
Journal ArticleDOI
Interaction of Hydrogen with Tungsten
TL;DR: In this paper, the authors measured the adsorption of hydrogen on tungsten, the rate of desorption, and the formation of atomic hydrogen by an incandescent filament.
Journal ArticleDOI
The Detection of Atoms and Free Radicals in Flames by Mass Spectrometric Techniques
S. N. Foner,R. L. Hudson +1 more
TL;DR: In this paper, a mass spectrometric method employing a molecular beam gas sampling system has been developed for the detection of atoms and radicals in chemical reactions, where background signals have been eliminated by mechanically modulating the molecular beam and applying phase detection to the ion signal.
Journal ArticleDOI
Molecular Dissociation and Reconstitution on Solids
TL;DR: In this article, the authors explored the dependence of heterogeneous reactions on the nature of the solid surface by analyzing the elementary rate processes involved, including the rates of adsorption, surface diffusion, and evaporation, and the depth and distribution of binding sites on the surface.