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Threshold behavior in electron-transfer collisions between rubidium atoms and C2F5Cl or C2F5I molecules
Beike Jia1, Sean Harris, Larry L Lewis
1Chemistry Department and Rice Quantum Institute, Rice University, Houston, TX 77251, USA.
The Journal of Physical Chemistry. A
|July 13, 2006
Summary
This study measured electron affinities of perfluoroethyl compounds using rubidium atom collisions. Anomalously high values for C(2)F(5)(-) were observed, likely due to Rb(2) impurities.
Area of Science:
- Atomic and Molecular Physics
- Chemical Physics
Background:
- Collisional ionization is a key process in understanding atomic and molecular interactions.
- Accurate measurement of electron affinities (EAs) is crucial for chemical and physical property predictions.
Purpose of the Study:
- To measure the electron affinity (EA) of iodoperfluoroethane (C(2)F(5)I) and perfluoroethyl radical (C(2)F(5)).
- To investigate the production of negative ions from chloroperfluoroethane and iodoperfluoroethane via atomic collisions.
- To identify and address sources of anomalously high EA values.
Main Methods:
- Accelerating rubidium (Rb) atoms in a high-temperature hydrogen expansion to generate high-energy beams.
- Measuring atom speeds using time-of-flight techniques.
- Detecting positive and negative ions in coincidence using separate mass spectrometers.
Main Results:
- Iodoperfluoroethane produced I(-), C(2)F(5)(-), and C(2)F(5)I(-) ions.
- Chloroperfluoroethane produced C(2)F(5)(-) and Cl(-) ions.
- The electron affinity of C(2)F(5)I was determined to be 0.96 ± 0.1 eV.
- Anomalously high EA values for C(2)F(5)(-) were observed, attributed to Rb(2) impurities.
Conclusions:
- The study successfully measured the EA of C(2)F(5)I using atomic collision techniques.
- The presence of Rb(2) impurities significantly impacted the measured EA of C(2)F(5)(-).
- This highlights the importance of high-purity atomic beams in accurate EA measurements.
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