Dissociative chemisorption of oxygen on Ir(110) as a function of angle of incidence: The effects of kinetic energy and surface temperature

1993 ◽  
Vol 11 (4) ◽  
pp. 1926-1929 ◽  
Author(s):  
R. W. Verhoef ◽  
D. Kelly ◽  
W. H. Weinberg
Keyword(s):  
Kinetic Energy ◽  
Surface Temperature ◽  
Angle Of Incidence ◽  
Dissociative Chemisorption

Dissociative Chemisorption at Hyperthermal Energies: Benchmark Studies in Group IV Systems

1995 ◽  
Vol 388 ◽  
Author(s):  
L.-Q. Xia ◽  
M. E. Jones ◽  
N. Maity ◽  
S. E. Roadman ◽  
J. R. Engstrom†
Keyword(s):  
Kinetic Energy ◽  
Group Iv ◽  
Reaction Probability ◽  
Angle Of Incidence ◽  
Dissociative Chemisorption ◽  
Reaction Conditions ◽  
Molecular Beam Scattering ◽  
Supersonic Molecular Beam ◽  
Universal Relationship ◽  
Incident Kinetic Energy

AbstractWe present a review of our recent work concerning supersonic molecular beam scattering of thin film precursors from the Si(100) and Si(111) surfaces. Both SiH4 and Si2H6 exhibit translationally activated dissociation channels at sufficiently high incident kinetic energies, (E┴) 0.5 eV. the dominant variables under our reaction conditions are the incident kinetic energy and the angle of incidence, whereas mean internal energy and substrate temperature play relatively minor roles. the former two variables couple to produce a universal relationship between the reaction probability and a scaled kinetic energy given by (E┴) = Eі[(l-Δ)cos2θі + 3Δsin2θі], where θі is the angle of incidence, a is a corrugation parameter, and 0 ≤ Δ ≤ 1. IN addition to the reaction probability, the reaction mechanism for Si2H6 is also dependent upon incident kinetic energy and surface structure, where a SiH4(g) production channel is observed on the Si(111)-(7x7) surface at low to moderate incident kinetic energies. the reactions of SiH3CH3 and PH3 provide convenient comparative examples. Methylsilane, reacting on a β-SiC surface, exhibits a translationally activated dissociation channel, similar to what is observed for SiH4 and Si2H6. Phosphine, on the other hand, exhibits the characteristics of trapping, precursor-mediated dissociative chemisorption. these results act to underscore the important role played by the frontier orbital topology, even at hyperthermal incident kinetic energies.

DISSOCIATIVE CHEMISORPTION OF H2(D2) AT Fe(110)

1994 ◽  
Vol 01 (04) ◽  
pp. 693-696 ◽  
Author(s):  
A. WIGHT ◽  
A. HODGSON ◽  
G. WORTHY ◽  
D. BUTLER ◽  
B.E. HAYDEN
Keyword(s):  
Surface Temperature ◽  
Experimental Error ◽  
Internal State ◽  
Incident Angle ◽  
Translational Energy ◽  
Surface Site ◽  
Dissociative Chemisorption ◽  
State Distribution ◽  
Energy Scaling ◽  
Low Energies

The dissociative chemisorption of H2(D2) at a Fe(110) surface has been studied as a function of translational energy ET, internal energy Ei, incident angle θi, and surface temperature Ts. Adsorption is activated, the sticking probability increasing steadily with translational energy with no evidence of a threshold for dissociation. Within experimental error there is no isotope effect or surface temperature dependence (180 K<Ts<400 K). Using seeded beams at constant translational energy, sticking on a clean surface is insensitive to the internal state distribution of the incident molecules, consistent with a barrier to dissociative chemisorption in the entrance channel. For translational energies below 0.2 eV sticking deviates from normal energy scaling, momentum parallel to the surface strongly inhibiting dissociative chemisorption. Dissociaton is interpreted in terms of a localised surface site for dissociative chemisorption at low energies.

Surface Temperature Effects on Dissociative Chemisorption of H2 on Cu(100)

2013 ◽  
Vol 117 (17) ◽  
pp. 8851-8863 ◽  
Author(s):  
Ali Marashdeh ◽  
Simone Casolo ◽  
Luca Sementa ◽  
Helmut Zacharias ◽  
Geert-Jan Kroes
Keyword(s):  
Surface Temperature ◽  
Temperature Effects ◽  
Dissociative Chemisorption

scholarly journals Estimating the effect of rainfall on the surface temperature of a tropical lake

2018 ◽  
Author(s):  
Gabriel Gerard Rooney ◽  
Nicole van Lipzig ◽  
Wim Thiery
Keyword(s):  
Heat Flux ◽  
Surface Layer ◽  
Kinetic Energy ◽  
Surface Temperature ◽  
Surface Air Temperature ◽  
Daily Rainfall ◽  
Tropical Lake ◽  
Lake Surface ◽  
Near Surface ◽  
Potential Control

Abstract. We make use of a unique high-quality, long-term observational dataset on a tropical lake to assess the effect of rainfall on lake surface temperature. The lake in question is Lake Kivu, one of the African Great Lakes, and was selected for its remarkably uniform climate and availability of multi-year, over-lake meteorological observations. Rain may have a cooling effect on the lake surface by lowering the near-surface air temperature, by the direct rain heat flux into the lake, by mixing the lake surface layer through the flux of kinetic energy, and by convective mixing of the lake surface layer. The potential importance of the rainfall effect is discussed in terms of both heat flux and kinetic-energy flux. To estimate the rainfall effect on the mean diurnal cycle of lake surface temperature, the data are binned into categories of daily rainfall amount. They are further filtered based on comparable values of daily mean net radiation, which reduces the influence of radiative-flux differences. Our results indicate that days with heavy rainfall may experience a reduction in lake surface temperature of approximately 0.3 K by the end of the day compared to days with light-to-moderate rainfall. Overall this study highlights a new potential control on lake surface temperature, and suggests that further efforts are needed to quantify this effect in other regions and to include this process in atmospheric models.

Evaluation of synchronizer loading parameters and their ability to predict failure

2017 ◽  
Vol 232 (9) ◽  
pp. 1093-1104 ◽  
Author(s):  
Daniel Häggström ◽  
Ulf Sellgren ◽  
Stefan Björklund
Keyword(s):  
Kinetic Energy ◽  
Service Life ◽  
Surface Temperature ◽  
Temperature Increase ◽  
Good Accuracy ◽  
Test Rig ◽  
Average Surface ◽  
Average Surface Temperature ◽  
Focal Surface ◽  
Short Service Life

Molybdenum coated gearbox synchronizers are tested in a μ-comp test rig under varying loading conditions until failure. Four different parameters used to describe the thermomechanical load are evaluated just before failure to compare their ability to predict failure. The parameters evaluated are the synchronized kinetic energy, the synchronization power, and the focal as well as the average surface temperature increase. The focal surface temperature increase as well as the average surface temperature increase is found to predict failure with relatively good accuracy. It is shown that there exists a threshold which divides the synchronizer into either a very long or a very short service life. Additionally, a method to determine the average surface temperature in the gearbox management system is proposed.

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