Predominance of CF-stretch vibrational excitation in state resolved inelastic scattering of protons from 11 small fluorohydrocarbon molecules
Time-of-flight spectra of H/sup +/ scattered from all ten different fluorinated hydrocarbon molecules of type CH/sub m/F/sub n/ and C/sub 2/H/sub m/F/sub n/ (m+n = 4) as well as C/sub 2/F/sub 6/ have been measured for small scattering angles (theta/sub lab/< or =15/sup 0/) at 9.8 eV collision energy. For the pure hydrocarbons the spectra show a complicated structure suggesting unresolved excitation of several modes and a significant effect of charge transfer collisions. In contrast all the spectra for fluorine containing molecules exhibit more or less sharp maxima indicating high overtone excitation of predominantly one vibrational mode with ..omega..approx. =1200 cm/sup -1/ corresponding to a CF-stretch vibration. At some scattering angles the overtone transition probabilities deviate somewhat from a Poisson distribution suggesting small unresolved contributions from additional vibrational modes. Over- all, however, there is good agreement for the low symmetry molecules, some of which have sizable dipole moments, with the predictions of the simple forced oscillator model previously tested only for the spherically symmetric molecules CF/sub 4/ and SF/sub 6/. The relative magnitudes of the observed energy transfers are consistent with absolute infrared intensities where these are available from the literature.
- Research Organization:
- Max Planck Institut fuer Stroemungsforschung, D 3400 Goettingen, Federal Republic of Germany
- OSTI ID:
- 6212976
- Journal Information:
- J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 82:1; ISSN JCPSA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ATOMIC IONS
CATIONS
CHARGE EXCHANGE
CHARGED PARTICLES
COLLISIONS
ENERGY LEVELS
ENERGY TRANSFER
ENERGY-LEVEL TRANSITIONS
EXCITATION
EXCITED STATES
FLUORINATED ALIPHATIC HYDROCARBONS
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROGEN IONS
HYDROGEN IONS 1 PLUS
ION COLLISIONS
ION-MOLECULE COLLISIONS
IONS
MOLECULE COLLISIONS
ORGANIC COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
VIBRATIONAL STATES