Heterogeneous Loss of Gas-Phase Ozone on n-Hexane Soot Surfaces: Similar Kinetics to Loss on Other Chemically Unsaturated Solid Surfaces

2008 ◽  
Vol 113 (6) ◽  
pp. 2120-2127 ◽  
Author(s):  
J. McCabe ◽  
J. P. D. Abbatt
Keyword(s):  
Gas Phase ◽  
Solid Surfaces

Etching Reactions at Solid Surfaces

1984 ◽  
Vol 38 ◽  
Author(s):  
Harold F. Winters ◽  
J. W. Coburn
Keyword(s):  
Experimental Data ◽  
Conceptual Framework ◽  
Gas Phase ◽  
Ion Bombardment ◽  
Solid Surfaces ◽  
Plasma Environment

AbstractAn understanding of etching reactions in a plasma environment requires a knowledge of: (1) the types of gas phase particles which react at the surface, (2) the etch products formed, and (3) the processes which lead from reactants to products. Experimental data relavant to these topics are reviewed in this paper. A conceptual framework for understanding the etching reaction is reviewed and it is shown that the experimental data presently available is consistent with this framework. The influence of ion bombardment on etching reactions is extensively discussed.

Band Effects on Ion-Surface Charge Exchange

1997 ◽  
Vol 11 (06) ◽  
pp. 685-706 ◽  
Author(s):  
Ryutaro Souda
Keyword(s):  
Gas Phase ◽  
Charge Exchange ◽  
Transition Probabilities ◽  
Noble Gas ◽  
Electron Excitation ◽  
Solid Surfaces ◽  
Hydrogen Ion ◽  
Surface Scattering ◽  
New Class ◽  
Low Energy Ions

Various aspects of charge exchange between low-energy ions (10 eV–2 keV) and solid surfaces are discussed with particular emphasis placed on the effects of valence orbital hybridization on the electronic transition probabilities, and uniqueness of surface scattering relative to diatomic gas-phase collision is highlighted. Two classes of projectiles are explored, i.e. inert noble-gas ions and a reactive hydrogen ion. One or two core vacancies are created in noble-gas projectiles during collisions with specific target atoms, leading to (re)ionization and autoionization. In contrast to gas-phase collision, it is found that one-electron excitation predominates over simultaneous two-electron excitation. This result is basically ascribed to the band effect of energy-level crossing. Neutralization of the slow hydrogen ion at a surface is rather unique compared to the noble-gas ions and its probability is sensitively dependent upon ionicity of target atoms or the nature of the valence band. This is because a valence electron is captured via a new class of resonance neutralization which is mediated by a short-lived chemisorption state of hydrogen on a surface.

Gas phase analysis of CO interactions with solid surfaces at high temperatures

2004 ◽  
Vol 233 (1-4) ◽  
pp. 392-401 ◽  
Author(s):  
Clara Anghel ◽  
Erik Hörnlund ◽  
Gunnar Hultquist ◽  
Magnus Limbäck
Keyword(s):  
Gas Phase ◽  
Phase Analysis ◽  
High Temperatures ◽  
Solid Surfaces

scholarly journals The interaction of atoms and molecules with solid surfaces VI—The behaviour of adsorbed helium at low temperatures

1937 ◽  
Vol 158 (894) ◽  
pp. 242-252 ◽  
Keyword(s):  
Gas Phase ◽  
Lithium Fluoride ◽  
Energy Levels ◽  
Heat Of Adsorption ◽  
Solid Surfaces ◽  
Potential Minimum ◽  
Helium Atoms ◽  
Finite Distance ◽  
Two Parameters ◽  
The Right

The heat of adsorption of helium atoms on solid surfaces is so small that no one has succeeded in measuring it directly. Its value could probably be inferred from a series of accurate measurements of adsorption isotherms by using the formulae given in Paper III of this series, or it could be calculated from known interatomic force fields as has sometimes been done. Such calculations indicate that the heat of adsorption on crystals of the rock salt type would probably be of the order of 100 to 200 cals./gm. atom. Another method of determining it has, however, been found in Paper V from the diffraction experiments of Frisch and Stern for these indicate that helium atoms on a lithium fluoride crystal have two quantized vibration levels perpendicular to the surface, whose energies are —57.5 cals, and —129 cals, (reckoned from a zero in which the atoms are in the gas phase at rest). The lower one gives the heat of adsorption. From these energy levels it is possible to deduce some information as to the nature of the potential field between helium atoms and lithium fluoride crystals by choosing a function of the right properties (such that it vanishes at infinity, gives attraction at large distances and repulsion at short distances, and has a minimum at a finite distance from the surface), for which the vibrational wave equation can be solved. Such a function is the Morse potential function, which contains two parameters D and k , the former giving the depth of the potential minimum and the latter the rate at which the field falls off (exponentially) at large distances. The two energy levels given above are thus sufficient to determine D and k and they are found to be —175 cals, and (1.10) 108 cm. -1 .

Evidence for nonclassical nucleation at solid surfaces in diamond deposition from the gas phase

1993 ◽  
Vol 8 (7) ◽  
pp. 1596-1604 ◽  
Author(s):  
Massimo Tomellini
Keyword(s):  
Gas Phase ◽  
Active Site ◽  
Rate Constants ◽  
Solid Surfaces ◽  
Silicon Surfaces ◽  
Necessary Condition ◽  
Nucleation Density ◽  
Diamond Deposition ◽  
Diamond Nucleation ◽  
Step Model

In the framework of a previously developed kinetic model, a discriminating criterion is established to distinguish between classical and nonclassical nucleation of diamond at solid surfaces. The two-step model gives the non-steady-state nucleation density function in terms of the rate constants for active site → germ, germ → active site, and germ → nucleus kinetic steps. The criterion states that α/β > 6 is a necessary condition for classical nucleation at surfaces to occur, α and β being functions of the rate constants which can be obtained by appropriate analysis of the experimental data. This criterion is applied to recent results on diamond nucleation at silicon surfaces and indicates nonclassical results The expression of the nonequilibrium Zeldovich factor, Z, is also found in the form Z = [1 + K/nd]−1, K and nd being the rate constants for the germ → nucleus and germ → active site steps, respectively. An estimation of the rate constants is reported and the corresponding Zeldovich factor is evaluated to be 0.6 for nucleation at both Si(100) and Si(111) substrates.

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