Articles you may be interested inDissociative electron attachment near threshold, thermal attachment rates, and vertical attachment energies of chloroalkanes Thermal electron attachment to NO. I. The mechanism and the threebody rate constants Electron dissociative attachment rate constants for F2 and NF3 at 300 and 500°K Appl. Phys. Lett. 35, 920 (1979); 10.1063/1.91005 Thermal energy electron attachment rate constants for some polyatomic molecules A flowing afterglow apparatus was constructed and used to measure thermal electron attachment rate constants in the halogen gases fluorine, chlorine, and bromine. The operation of the afterglow system and the mathematical models applied in treating the data were tested by measuring the thermal attachment rate constant for electrons in sulfur hexafluoride. The average value obtained for this rate constant is 4.2± 1.1 X 10-8 cm' molecule-1 sec-1 when a microwave discharge was used as the electron source and 3.6± 1.8x 10-8 cm' molecule-1 sec-1 when a filament was used as the electron source. The average electron temperature was estimated to be approximately 6OO'K for the microwave discharge source and approximately 350'K for the filament source. A charge transfer reaction between sulfur hexafluoride and the ion O 2 was also investigated in the present study to further assess the operation of the flowing afterglow apparatus in the microwave discharge source configuration, The average rate constant obtained for this reaction is 3.7 ±O.4X 10-11 cm' molecule-1 sec-1 for an estimated ion temperature of 300-325'K, The average rate constants obtained for the dissociative attachment of electrons in fluorine are 4.6±1.2XIO-9 cm' molecule-1 sec-1 for an electron temperature of approximately 600'K and 3.1 ± 1.2X 10-9 cm' molecule" 1 sec-1 for an electron temperature of approximately 350'K. The average rate constants obtained for dissociative electron attachment in chlorine and bromine are 3.7± 1.7X 10,·9 and I.O±O.9X 10-11 cm' molecule-1sec-1 , respectively, for an electron temperature of approximately 350'K, The rate constant for the three-body attachment reaction Br-+Br,+Ar to form Bri' was also measured and found to be 1.9±O.5XIO-28 cm 6 molecule--'sec· 1 .

The rate constant for the dissociative attachment of thermal elections (300−350 °K) to nitrogen trifluoride has been measured using a flowing afterglow technique. (AIP)

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The application of low-energy molecular-beam techniques to the analysis of the neutral (metastable and ground-state) particles emitted by a thermal plasma is described. The technique is illustrated with the use of an apparatus that contains a rotating slotted-disk velocity analyzer and an inhomogeneous-field deflecting magnet. The beam source is a hot-cathode low-voltage continuous discharge in a rare gas. With this apparatus the Landé g factor was found to be 1.51 ± 0.01 for Ne 3P2 and 1.50 ± 0.02 for Ar 3P2, in accord with theory. In addition, measurement of the velocity distributions of the two Ne metastable atoms (3P0 and 3P2) demonstrated that they could be characterized by Maxwell-Boltzmann distribution functions with different temperatures for the two states.

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