Study of the symmetric charge transfer reaction H/sup +//sub 2/+H/sub 2/ using the high resolution photoionization and crossed ion--neutral beam methods
A new ion--molecule reaction apparatus, which combines the crossed ion--neutral beam method, high resolution photoionization mass spectrometry, and charge transfer detection, has been developed. Using this apparatus, we have examined the relative total charge transfer cross sections of H/sup +//sub 2/+H/sub 2/ as a function of the vibrational state of H/sup +//sub 2/, v/sup prime//sub 0/ = 0--4, at the center-of-mass collision energy (E/sub c.m./) range of 0.38--200 eV. The relative total charge transfer cross sections measured at E/sub c.m./ = 8, 16, 22.5, and 200 eV are in general agreement with a recent theoretical calculation based on the semiclassical energy conserving trajectory formulation. The vibrational energy effects on the cross sections for the charge transfer and the H/sup +//sub 3/+H channels at low collision energies (E/sub c.m./ < or =1 eV) were directly observed. The rotational states, J = 0, 1, and 2, of H/sup +//sub 2/(v/sup //sub 0/ = 0) were also selected in this experiment. Within experimental uncertainties, the rotational excitations of H/sup +//sub 2/(v/sup prime//sub 0/ = 0) have no effect on the relative total charge transfer cross sections at E/sub c.m./ = 2 and 4 eV. By calibrating the nominal relative total charge transfer cross sections obtained with an ionizing photon energy of 18 eV (688 A) to absolute total charge transfer cross sections determined previously using low energy electron impact ionization, absolute total charge transfer cross sections for v/sup //sub 0/ = 0 and 1 in the kinetic energy range of E/sub c.m./ = 8--200 eV were estimated. The absolute total charge transfer cross sections thus obtained for v/sup prime//sub 0/ = 0 and 1 are lower than the theoretical values by approximately a factor of 2.
- Research Organization:
- Ames Laboratory, U. S. Department of Energy and Department of Chemistry, Iowa State University, Ames, Iowa 50011
- DOE Contract Number:
- W-7405-ENG-82
- OSTI ID:
- 6212822
- Journal Information:
- J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 81:12; 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
BEAMS
CATIONS
CHARGE EXCHANGE
CHARGED PARTICLES
CHEMICAL REACTIONS
COLLISIONS
ELEMENTS
HYDROGEN
HYDROGEN IONS
HYDROGEN IONS 1 PLUS
ION BEAMS
ION COLLISIONS
ION-MOLECULE COLLISIONS
IONIZATION
IONS
MASS SPECTROSCOPY
MOLECULAR BEAMS
MOLECULAR IONS
MOLECULE COLLISIONS
NONMETALS
PHOTOIONIZATION
SPECTROSCOPY