Effect of temperature on the dissociative electron attachment to CClF/sub 3/ and C/sub 2/F/sub 6/
The total electron attachment rate constant k/sub a/() for CClF/sub 3/ and C/sub 2/F/sub 6/ has been meausured using an electron swarm technique in the mean electron energy range 0.41 to 4.81 eV and over the range of temperature T from 300 to 750 K. At each value of T the total electron attachment cross section sigma/sub a/(epsilon) was determined from the measured k/sub a/() using the swarm unfolding technique and was compared with the results of a mass spectrometric study. The sigma/sub a/(epsilon) for C/sub 2/F/sub 6/ shows a single peak (due to F/sup -/ and CF/sub 3//sup -/) which shifts from 3.9 eV at 300 K to approx.3.3 eV at 750 K. (The onset shifts correspondingly from 2.3 to 1.5 eV.) For CClF/sub 3/ the sigma/sub a/(epsilon) shows two peaks: at approx.1.5 eV (due to Cl/sup -/) and at approx.4.7 eV (due to Cl/sup -/, F/sup -/, CClF/sub 2//sup -/, and ClF/sup -/). The peak at approx.1.5 eV is especially sensitive to changes in T. The peak value of sigma/sub a/(epsilon) increased by a factor of approx.3, and the energy position of the peak and onset shifted to progressively lower energies when T increased from 300 to 700 K. The analysis of these results led us to conclude that the changes in k/sub a/() and sigma/sub a/(epsilon) for the dissociative attachment processes of these molecules with increasing T result from the increase with T of the total internal (approx. = vibrational) energy of the molecule.
- Research Organization:
- Atomic, Molecular, and High Voltage Physics Group, Health and Safety Research Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 5923411
- Journal Information:
- J. Chem. Phys.; (United States), Vol. 82:6
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CHLORINATED ALIPHATIC HYDROCARBONS
ELECTRON-MOLECULE COLLISIONS
DISSOCIATION
ELECTRON ATTACHMENT
FLUORINATED ALIPHATIC HYDROCARBONS
CHEMICAL REACTION KINETICS
HIGH TEMPERATURE
MEDIUM TEMPERATURE
TEMPERATURE DEPENDENCE
COLLISIONS
ELECTRON COLLISIONS
HALOGENATED ALIPHATIC HYDROCARBONS
KINETICS
MOLECULE COLLISIONS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
REACTION KINETICS
640304* - Atomic
Molecular & Chemical Physics- Collision Phenomena