scholarly journals Design of a molecular beam surface scattering apparatus for velocity and angular distribution measurements

1981 ◽  
Vol 19 (3) ◽  
pp. 726-732 ◽  
Author(s):  
S. T. Ceyer ◽  
W. J. Siekhaus ◽  
G. A. Somorjai
Keyword(s):  
Angular Distribution ◽  
Molecular Beam ◽  
Surface Scattering ◽  
Beam Surface

Molecular beam-surface scattering

Vacuum ◽  
1981 ◽  
Vol 31 (10-12) ◽  
pp. 647-657 ◽  
Author(s):  
F Tommasini
Keyword(s):  
Molecular Beam ◽  
Surface Scattering ◽  
Beam Surface

scholarly journals Effect of N atoms on O-Atom Reactivity with Carbon

2020 ◽  
Author(s):  
Chenbiao Xu ◽  
Timothy Minton
Keyword(s):  
High Temperature ◽  
Surface Temperature ◽  
Molecular Beam ◽  
Catalytic Effect ◽  
Surface Scattering ◽  
Carbon Surface ◽  
Vitreous Carbon ◽  
Finite Rate ◽  
Detailed Explanation ◽  
Beam Surface

Molecular beam-surface scattering experiments have been used to study the effect of N atoms on the reactivity of O atoms with a high-temperature carbon surface to produce CO. The CO flux produced from bombardment of a vitreous carbon surface by a beam containing N and O atoms was compared with the CO flux produced from bombardment by beams containing either N or O atoms. The presence of small mole fractions of N atoms of 0.02-0.08 enhanced the reactivity of O atoms by a factor of 1.4-1.6 in the range of surface temperatures from 1100 to 1700 K. A detailed explanation of the observed results requires more study, but it appears that N atoms can act as a catalyst to increase the reactivity of O with carbon and that a relatively low flux of N atoms may be sufficient to saturate the catalytic effect. This catalytic effect seems to be fairly insensitive to the surface temperature, at least over the temperature range used in this study. This observation is important in the development of finite-rate models of air-carbon ablation during hypersonic flight.

A molecular beam surface scattering study of ammonia oxidation on the platinum(111) crystal face

1984 ◽  
Vol 88 (15) ◽  
pp. 3233-3238 ◽  
Author(s):  
M. Asscher ◽  
W. L. Guthrie ◽  
T. H. Lin ◽  
G. A. Somorjai
Keyword(s):  
Molecular Beam ◽  
Ammonia Oxidation ◽  
Surface Scattering ◽  
Crystal Face ◽  
Beam Surface ◽  
Scattering Study

scholarly journals Effect of N atoms on O-Atom Reactivity with Carbon

2020 ◽  
Author(s):  
Chenbiao Xu ◽  
Timothy Minton
Keyword(s):  
High Temperature ◽  
Surface Temperature ◽  
Molecular Beam ◽  
Catalytic Effect ◽  
Surface Scattering ◽  
Carbon Surface ◽  
Vitreous Carbon ◽  
Finite Rate ◽  
Detailed Explanation ◽  
Beam Surface

Molecular beam-surface scattering experiments have been used to study the effect of N atoms on the reactivity of O atoms with a high-temperature carbon surface to produce CO. The CO flux produced from bombardment of a vitreous carbon surface by a beam containing N and O atoms was compared with the CO flux produced from bombardment by beams containing either N or O atoms. The presence of small mole fractions of N atoms of 0.02-0.08 enhanced the reactivity of O atoms by a factor of 1.4-1.6 in the range of surface temperatures from 1100 to 1700 K. A detailed explanation of the observed results requires more study, but it appears that N atoms can act as a catalyst to increase the reactivity of O with carbon and that a relatively low flux of N atoms may be sufficient to saturate the catalytic effect. This catalytic effect seems to be fairly insensitive to the surface temperature, at least over the temperature range used in this study. This observation is important in the development of finite-rate models of air-carbon ablation during hypersonic flight.

Surface Chemistry of CVD Reactions Studied by Molecular Beam/Surface Scattering

1990 ◽  
Vol 204 ◽  
Author(s):  
Ming L. Yu ◽  
Ulrich Memmert ◽  
Nicholas I. Buchan ◽  
Thomas F. Kuech
Keyword(s):  
Surface Chemistry ◽  
Real Time ◽  
Gas Phase ◽  
Molecular Beam ◽  
Substrate Surface ◽  
Atomic Layer ◽  
Molecular Beams ◽  
Surface Scattering ◽  
Reaction Products ◽  
Beam Surface

ABSTRACTA molecular beam/surface scattering experiment in an ultrahigh vacuum is conceptually a simulation of a CVD reactor without the interference from gas phase and wall reactions. The surface chemistry can be studied in real-time during the deposition reaction at the desired temperature. In our experiment, we used pulsed molecular beams of the reactants and a mass spectrometer to monitor In real-time the reaction products evolving from the substrate surface. With this arrangement, the reaction probability of the molecules can readily be determined by measuring the unreacted fraction of the molecular beam. The reaction pathways can be deduced from the Identification of the reaction products, while their time-evolutions give the kinetic parameters. We shall illustrate this technique by our study on the reactions of trimethylgallium and triethylgallium on GaAs as related to the metalorganic CVD and atomic layer epitaxy of GaAs.

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