Time of flight measurements of the vibrational excitation of CO/sub 2/ and N/sub 2/O by collision with 3--8 eV Li/sup +/ ions
The relative differential cross sections for the excitation of the first few vibrationally excited states of CO/sub 2/ and N/sub 2/O by collision with Li/sup +/ ions have been measured by the time of flight technique in a crossed beam scattering experiment. The individual vibrational transitions between the ground state and the first excited bending mode and stretching mode have been resolved for various center of mass energies between 3.0 and 6.9 eV and center of mass angles in the range of 9degree to 35degree. These angles are larger than the rainbow angle, indicating that the repulsive part of the intermolecular potential was sampled. Both CO/sub 2/ and N/sub 2/O exhibit little rotational excitation. At nearly all angles and energies, CO/sub 2/ shows more vibrational excitation than the equally massive N/sub 2/O. The bending mode excitation is particularly strong in CO/sub 2/. Evidence is presented to show that these differences and the lack of rotational excitation cannot be explained purely by differences in the masses of the constituent atoms but must be due to significant differences in the intermolecular potentials. The CO/sub 2/ observations can be qualitatively explained by a simple potential model involving coulomb forces between the Li/sup +/ ion and charges on the atoms of the molecule which are chosen to give the known quadrupole moment. From the rainbow structure of the measured total differential cross sections, the effective depth of the intermolecular potential well was estimated to be 0.52 eV for both systems.
- Research Organization:
- Max-Planck-Institut fuer Stroemungsforschung, 3400 Goettingen, Boettingerstr. 6-8, West Germany
- OSTI ID:
- 7124400
- Journal Information:
- J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 66:5; 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
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
CHARGED PARTICLES
COLLISIONS
CROSS SECTIONS
DIFFERENTIAL CROSS SECTIONS
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITATION
EXCITED STATES
ION COLLISIONS
ION-MOLECULE COLLISIONS
IONS
LITHIUM IONS
MOLECULE COLLISIONS
NITROGEN COMPOUNDS
NITROGEN OXIDES
OXIDES
OXYGEN COMPOUNDS
TIME-OF-FLIGHT METHOD
VIBRATIONAL STATES