Discharge chemistry

Pinder, G. F. Jones, J. F. 1969. Determination of the groundwater component of peak discharge chemistry of total runoff. Water Resouces Research, 5, 438-445. 

It would appear that the elemental gas-phase process of major importance to gas discharge chemistry is electron impact excitation, for this... 

Radiation Chemistry and Electric Discharge Chemistry Comparison and Contrast... 

Radiation chemistry and discharge chemistry have in common the feature that they are extremely complicated. Further, if one were to divide chemistry into two areas, in the first of which the individual features could conceivably be accurately measured and in the second of which only qualitative features are discernible, both would appear to belong in the first category. Nevertheless, in spite of the fact that individual features can be quantitatively studied, the synthesis of the understanding of the individual items into a complete theory is still so remote as to rouse the suspicion that, if neither belongs in the second category, it should not yet be admitted to the first. 

On the other hand, if we are to understand radiation chemistry and discharge chemistry at all we must understand them in terms of elementary process, instead of in terms of over-all effects which can be so readily observed. We establish the reality of such elementary processes for the most part on an essentially intuitive basis. We are of the opinion that we know that certain elementary processes occur in radiation chemistry or in discharge chemistry because of observations made, for example, in cloud-chamber experiments or in mass spectroscopy. We conclude... 

Suppose we could assume both radiation chemistry and discharge chemistry to be sufficiently developed so that we could examine the components in this kind of detail. The next step would be to make the contrasts suggested in the title of this article. We would select components which in our opinion contribute the major characteristic of the particular branch. We would compare them with each other. We would compare the specifically important and contrasting ways in which they interact in the two cases. Such procedure would appear to be very logical indeed. 

With apology for an attempt at comparison and contrast clearly stated, and with the implicit reservations indicated, it is appropriate to consider the major differences between radiation chemistry (5) and discharge chemistry. 

The over-all results in radiation chemistry can be expected to differ from those in discharge chemistry because of two essentially different groups of facts, namely those associated with the initial physical aspects and those associated with what, for convenience, we hereinafter call chemical physics, namely those processes in the exposed material which involve the actual production and distribution of different excited states. The classes of effects are summarized in Tables I and II. 

In general in radiation chemistry, the energy of any important primary particle (which we henceforth consider to be an electron) is greater than — 500 Kev. and in discharge chemistry < 15 e.v. The former value... 

Finally, there is one additional respect in which the chemical physics of radiation chemistry differs from that of discharge chemistry. The probability, in radiation chemistry, that a molecule may suffer a second interaction or that a product from a molecule which has been decomposed may itself be acted upon by an exciting species is extremly small—except in cases where the radiation is so intense that it is hardly of present theoretical or experimental interest. In discharge chemistry, the probability of such processes is very high indeed. Thus, the effect of successive excitations must be considered and it must also be considered possible... 

This is a particularly good place to emphasize a point implied by the Introduction. Although the special importance of vibrationally highly excited species in discharge chemistry may be easily invoked, we must at the same time not neglect the totality of phenomena in which they may be involved and affected by all the conditions and by all the intermediate species peculiar to the electric discharge. 

For the most part, the ultimate objective of this research is the production of new and useful products or the production of known products at less cost. Thus, the essential background of information already developed by the physicist, electrochemist, chemical and electrical engineer must be brought together in a manner that is readily understood by each. The papers presented in this volume reflect this diversity of interest in discharge chemistry. 

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