Third Report of the Committee on Photochemistry Reprint and Circular Series of the National Research Council (1938) / Chapter Skim
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Secondary Processes in the Photodecomposition of Ammonia and Hydrozine
Secondary Processes in the Photodecomposition of Ammonia and Hydrozine
Pages 85-90
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From page 85... ...
cannot be excluded on energetic grounds. It would, however, suggest an influence of molecular hydrogen which is not found experimentally in the photoreaction, although there is an effect in the reaction initiated by a-particles and ions, in which case, at higher pressures, NH+ is certainly formed by secondary processes.
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From page 86... ...
Alkali metals virtually completely dissociate in liquid ammonia into positive metal ions and free electrons which become strongly solvated with the ammonia. It would appear, therefore, that in pure liquid ammonia deactivation or primary recombination effectively retards the decomposition, while in the presence of solvated electrons the NH2 radicals are stabilized by the formation of amide ion, thus permitting the decomposition to proceed.
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From page 87... ...
is the velocity of reaction expressed as the number of molecules of ammonia decomposed to nitrogen and hydrogen per cubic centimeter per second, P is the total pressure, and ~ the quantum yield equal to Q/v, where Q is the number of ammonia molecules per cubic centimeter per second primarily decomposed.
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From page 88... ...
The Mund-van Tiggelen numerical values for the relative rates of the several reactions do not constitute a unique solution, as is evident from an analysis by Leighton (89. :For the ratios 20:17:16:1:2 of the above sequence, Leighton substitutes the sequence lO(NH3 + ho = NH2 + H)
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From page 89... ...
To introduce such possibilities into the kinetic scheme would further complicate the equation derived' and the experimental data at present are not accurate enough to justify, such further refinements. In the ammonia-sensitized hydrazine decomposition experiments of Ogg, Leighton, and Bergstrom, the two initial stages are quite clear, namely' reactions 1 and 5 of the ammonia scheme above.
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From page 90... ...
Wenner and Beckmann (17) found quantum yields ranging from 1 at low pressures to 1.7 at higher pressures and hydrogen concentrations ranging from 58 to 64 per cent in the same pressure range of 2 to 14 mm., decreasing toward 50 per cent with · .
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