Electron attachment to the perfluoroalkanes n-C/sub N/F/sub 2N/+2 (N = 1--6) and i-C/sub 4/F/sub 10/

Journal Article · Wed Jun 15 04:00:00 EDT 1983 · J. Chem. Phys.; (United States)

OSTI ID:6238795

Spyrou, S M; Sauers, I; Christophorou, L G

Parent and fragment negative ion formation from seven perfluoroalkanes (n-C/sub N/F/sub 2N/+2 (N = 1--6) and i-C/sub 4/F/sub 10/) under low-energy (0--10 eV) electron impact has been studied using a time-of-flight mass spectrometer. For CF/sub 4/, C/sub 2/E/sub 6/, and C/sub 3/F/sub 8/ only fragment anions were observed, F/sup -/ being the most abundant. For n-C/sub 4/F/sub 10/ a weak parent ion was observed, but again the predominant ion was F/sup -/. For i-C/sub 4/F/sub 10/, n-C/sub 5/F/sub 12/, and n-C/sub 6/F/sub 14/ the parent negative ions were the most abundant with relative cross sections peaking at 0.6 eV and autodetachment lifetimes from 10 to 100 ..mu..s depending on the molecular size and electron energy. In addition to the parent negative ion and the F/sup -/ ion, fragment negative ions of the form C/sub N/F/sup -//sub 2N/+1, C/sub N/F/sup -//sub 2N/, C/sub N/F/sup -//sub 2N/-1 (with N = 1--6) have been detected. The relative cross sections for all observed negative ions have been measured and corrected for the finite width of the electron pulse using an unfolding procedure. The positions of the dissociating negative ion states (NISs) shift to lower energies with increasing size of the molecule. Possible fragmentation mechanisms of the NISs leading to the production of the observed fragment negative ions have been suggested and discussed. From the appearance onsets of a number of fragment negative ions, various C--C and C--F bond dissociation energies, heats of formation, and electron affinities EA of certain fragments have been determined and are reported.

• Research Organization: Atomic, Molecular, and High Voltage Physics Group, Health and Safety Research Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830
• OSTI ID: 6238795
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 78:12; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
AFFINITY
ANIONS
CHARGED PARTICLES
COLLISIONS
ELECTRON ATTACHMENT
ELECTRON COLLISIONS
ELECTRON-MOLECULE COLLISIONS
ELECTRONEGATIVITY
ENERGY RANGE
ENTHALPY
EV RANGE
EV RANGE 01-10
FLUORINATED ALIPHATIC HYDROCARBONS
FORMATION HEAT
HALOGENATED ALIPHATIC HYDROCARBONS
IONIZATION
IONS
MASS SPECTROSCOPY
MOLECULE COLLISIONS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
PHYSICAL PROPERTIES
REACTION HEAT
SPECTROSCOPY
THERMODYNAMIC PROPERTIES