Molecular dissociation in a constricted glow discharge
| Autor: | P H Richards, D T Swift-Hook, R H Varey, J Smalley, C F Gozna |
|---|---|
| Rok vydání: | 1971 |
| Předmět: |
Glow discharge
Acoustics and Ultrasonics Hydrogen Chemistry Analytical chemistry chemistry.chemical_element Plasma Condensed Matter Physics Mass spectrometry Dissociation (chemistry) Cathode Surfaces Coatings and Films Electronic Optical and Magnetic Materials Electric discharge in gases law.invention law Excited state |
| Zdroj: | Journal of Physics D: Applied Physics. 4:1520-1526 |
| ISSN: | 0022-3727 |
| DOI: | 10.1088/0022-3727/4/10/309 |
| Popis: | This paper describes the characteristics and potential uses for plasma chemistry of the sac which occurs at a constriction in a dc glow discharge (SESER). It is found that the rate at which molecules are dissociated is increased in the presence of a plasma sac; in the sac itself the dissociation rate per unit volume can be three orders of magnitude greater than in the positive column. Plasma sacs have been produced in an ammonia discharge with currents in the range 50 to 600 mA, pressures between 0·02 and 2·0 Torr and flow rates of 0·1 to 14 mg s−1, the direction of flow being through the plasma sac from anode to cathode. The dissociation of ammonia to hydrogen and nitrogen has been measured with a mass spectrometer. Optical spectra show that the intensity of all lines is higher in the plasma sac than in the positive column; hydrogen lines, Hα and Hβ are seen in the sac but not in any other region of the discharge. Strong NH lines are seen but none from NH2 and it is concluded that excited NH radicals may play an important role in the dissociation process. The high dissociation rates and intense spectra appear to be caused by the high-energy electrons in the plasma sac. A constriction in a gas discharge (SESER) appears to have interesting potentialities for plasma chemistry. |
| Databáze: | OpenAIRE |
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