title: Threshold behavior in electron-transfer collisions between rubidium atoms and C2F5Cl or C2F5I molecules.
abstract: Rubidium atoms are accelerated in a high-temperature expansion of hydrogen to produce beams with energies high enough to observe collisional ionization with a cross beam. The speed of the atoms is directly measured by time-of-flight techniques, and the positive and negative ions produced are detected in separate mass spectrometers and detected in coincidence. Chloroperfluoroethane produces C(2)F(5)(-) and Cl(-) ions, whereas iodoperfluoroethane produces I(-), C(2)F(5)(-), and C(2)F(5)I(-) ions. When the measured speed distributions are used, the signal versus energy may be deconvolved to yield thresholds and electron affinities (EAs). The EA for C(2)F(5)I is measured to be 0.96 +/- 0.1 eV. Anomalously high EA values result for C(2)F(5) apparently because C(2)F(5)(-) is produced by parts per million concentrations of Rb(2).
authors.affiliation: Chemistry Department and Rice Quantum Institute, Rice University, Houston, TX 77251, USA.
authors.forename: Beike
authors.initials: B
authors.lastname: Jia
authors.forename: Sean
authors.initials: S
authors.lastname: Harris
authors.forename: Larry L
authors.initials: LL
authors.lastname: Lewis
authors.forename: Jiping
authors.initials: J
authors.lastname: Zhan
authors.forename: Philip R
authors.initials: PR
authors.lastname: Brooks
mesh_terms: D004579:Electron Transport; D013058:Mass Spectrometry; D012413:Rubidium / Q000737:chemistry*
chemical_list: D012413:Rubidium