Radiolysis and Energy Transfer in the Adsorbed State

1966 ◽  
Vol 70 (4) ◽  
pp. 1098-1107 ◽  
Author(s):  
J. G. Rabe ◽  
Birgit Rabe ◽  
A. O. Allen
Keyword(s):  
Energy Transfer ◽  
Adsorbed State

The irradiation of alkyl siloxanes in the adsorbed state. Part 3. The irradiation chemistry of hexamethyldisiloxane adsorbed onto silica

1983 ◽  
Vol 61 (4) ◽  
pp. 729-733
Author(s):  
K-S. Maeng ◽  
G. R. Brown ◽  
G. J. Trudel ◽  
L. E. St-Pierre
Keyword(s):  
Energy Transfer ◽  
Chemical Reactions ◽  
Adsorbed Layer ◽  
Cross Linking ◽  
Adsorbed State ◽  
Γ Irradiation ◽  
Enhanced Production ◽  
Production Of Hydrogen ◽  
Chemical Cross Linking

Enhanced production of hydrogen, methane, and ethane from the γ-irradiation of hexamethyldisiloxane (MM) adsorbed onto silica compared to that from liquid MM results from energy transfer from the solid to the adsorbed layer. Chemical reactions with the surface are shown by deuterated products from the irradiation of MM on a deuterated silica and from extensive chemical cross-linking to the surface. These reactions predominate in the first monolayer of coverage.

Radiolysls In the adsorbed state. III. Methyl iodide adsorbed on silica gel

1970 ◽  
Vol 48 (1) ◽  
pp. 17-23 ◽  
Author(s):  
N. H. Sagert ◽  
J. A. Reid ◽  
R. W. Robinson
Keyword(s):  
Energy Transfer ◽  
Silica Gel ◽  
Methyl Iodide ◽  
Large Fraction ◽  
Adsorbed State ◽  
Surface Hydroxyl ◽  
Electron Scavenger ◽  
Surface Hydroxyls ◽  
Chemical Reactant ◽  
Surface Changes

The 60Co γ-radiolysis of methyl iodide adsorbed on silica gel has been studied by examining the hydrocarbon products, which are mainly methane and ethane. These products are formed in large yields, indicating that a large fraction of the energy absorbed in the silica gel is able to cause decomposition of the methyl iodide. The “energy transfer” is thought to occur by electron or excitation transfer to the methyl iodide, leading to the production of methyl radicals.Evidence has been obtained that the silica gel takes part in the system as a chemical reactant as well as being an energy transfer medium, and that changing the nature of the surface changes the course of the reaction. This is most clearly shown in two ways. The ratio of methane to ethane decreases as the surface hydroxyl concentration decreases, and it is concluded that excited methyl radicals form methane by abstraction of hydrogen from surface hydroxyls. Experiments using methyl iodide-d3 adsorbed on protiated silica gel confirm the participation of hydrogen from the silica gel, as the methane is over 85% CD3H, while the ethane is over 95% C2D6.The effect of additives such as N2O and SF6, which are known to be electron scavengers, was also studied. It was shown that methyl iodide is a much better electron scavenger than N2O and is as good an electron scavenger as SF6 in this system.

A quantitative approach to inner shell losses

1978 ◽  
Vol 36 (1) ◽  
pp. 526-527 ◽  
Author(s):  
R.D. Leapman ◽  
P. Rez ◽  
D.F. Mayers
Keyword(s):  
Energy Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Accurate Determination ◽  
Background Intensity ◽  
Core Excitation ◽  
Quantitative Basis ◽  
Cross Section Differential ◽  
Bound Electrons

Microanalysis by EELS has been developing rapidly and though the general form of the spectrum is now understood there is a need to put the technique on a more quantitative basis (1,2). Certain aspects important for microanalysis include: (i) accurate determination of the partial cross sections, σx(α,ΔE) for core excitation when scattering lies inside collection angle a and energy range ΔE above the edge, (ii) behavior of the background intensity due to excitation of less strongly bound electrons, necessary for extrapolation beneath the signal of interest, (iii) departures from the simple hydrogenic K-edge seen in L and M losses, effecting σx and complicating microanalysis. Such problems might be approached empirically but here we describe how computation can elucidate the spectrum shape.The inelastic cross section differential with respect to energy transfer E and momentum transfer q for electrons of energy E0 and velocity v can be written as

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