Time-of-flight studies of rotational quantum excitation of H/sub 2/ in collision with protons at E/sub c. //sub m. /=3. 7 eV
In a crossed beam apparatus, a monoenergetic pulsed proton ion beam is scattered from a nozzle beam of n-H/sub 2/ or p-H/sub 2/ in their rotational ground states. The energy loss of the scattered ions is analyzed using a time-of-flight technique. Rotational quantum transitions corresponding to ..delta.. j up to 20 could be resolved in the angular region of 0< or =55degree, which extends up to the rainbow angle. Only a small amount of vibrational excitation is obtained at E/sub c.//sub m./=3.7 eV. The measured time-of-flight spectra have been transformed into the center of mass system to provide distributions of relative transition probabilities. These agree qualitatively with the predictions of Giese and Gentry based on Monte Carlo averaged classical trajectories for 10 eV. The measured probability distribution has a maximum for elastic scattering (..delta..j=0) at all angles. It drops to between 5% and 35% for ..delta..j=2 transitions, and for most angles decreases only gradually with increasing ..delta..j. At center of mass angles of 15degree and 23degree, the rotational probability distribution shows a second distinct maximum at ..delta..j=8. At angles greater than 27degree, the transition probability distribution falls off nearly monotonically. The first moment of the energy loss distribution shows two maxima at about 23degree and 30degree. The largest maximum at 30degree, which is roughly one-half the rainbow angle, was predicted by Giese and Gentry. (AIP)
- Research Organization:
- Max-Planck-Institut fuer Stroemungsforschung 34 Goettingen, Boettingerstr. 6-8, West Germany
- OSTI ID:
- 7139265
- Journal Information:
- J. Chem. Phys.; (United States), Vol. 65:11
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
HYDROGEN
ION-MOLECULE COLLISIONS
HYDROGEN IONS 1 PLUS
EV RANGE 01-10
EXCITATION
ROTATIONAL STATES
CATIONS
CHARGED PARTICLES
COLLISIONS
CRYOGENIC FLUIDS
ELEMENTS
ENERGY LEVELS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EV RANGE
EXCITED STATES
FLUIDS
HYDROGEN IONS
ION COLLISIONS
IONS
MOLECULE COLLISIONS
NONMETALS
640304* - Atomic
Molecular & Chemical Physics- Collision Phenomena