Forward electron production in heavy ion-atom and ion-solid collisions
A sharp cusp in the velocity spectrum of electrons, ejected in ion-atom and ion-solid collisions, is observed when the ejected electron velocity vector v/sub e/ matches that of the emergent ion vector v/sub p/ in both speed and direction. In ion-atom collisions, the electrons originate from capture to low-lying, projectile-centered continuum states (ECC) for fast bare or nearly bare projectiles, and from loss to those low-lying continuum states (ELC) when loosely bound projectile electrons are available. Most investigators now agree that ECC cusps are strongly skewed toward lower velocities, and exhibit full widths half maxima roughly proportional to v/sub p/ (neglecting target-shell effects, which are sometimes strong). A close examination of recent ELC data shows that ELC cusps are instead nearly symmetric, with widths nearly independent on v/sub p/ in the velocity range 6 to 18 a.u., a result only recently predicted by theory. Convoy electron cusps produced in heavy ion-solid collisions at MeV/u energies exhibit approximately velocity-independent widths very similar to ELC cusp widths. While the shape of the convoy peaks is approximately independent of projectile Z, velocity, and of target material, it is found that the yields in polycrystalline targets exhibit a strong dependence on projectile Z and velocity. While attempts have been made to link convoy electron production to binary ECC or ELC processes, sometimes at the last layer, or alternatively to a solid-state wake-riding model, our measured dependences of cusp shape and yield on projectile charge state and energy are inconsistent with the predictions of available theories. 10 references, 8 figures, 1 table.
- Research Organization:
- Tennessee Univ., Knoxville (USA); Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6496676
- Report Number(s):
- CONF-840829-3; ON: DE85001256
- Resource Relation:
- Conference: International conference on x-ray and inner-shell processes in atoms, molecules and solids, Leipzig, Germany D.R., 20 Aug 1984
- Country of Publication:
- United States
- Language:
- English
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Convoy electron production in heavy-ion-solid collisions
Experiments concerning electron capture and loss to the continuum and convoy electron production by highly ionized projectiles in the 0. 7--8. 5-MeV/u range traversing the rare gases, polycrystalline solids, and axial channels in gold
Related Subjects
ARGON
ION-ATOM COLLISIONS
SECONDARY EMISSION
OXYGEN IONS
ANGULAR DISTRIBUTION
COLLISIONS
ELECTRON EMISSION
EXPERIMENTAL DATA
HEAVY IONS
MEV RANGE 10-100
MULTICHARGED IONS
VELOCITY
ATOM COLLISIONS
CHARGED PARTICLES
DATA
DISTRIBUTION
ELEMENTS
EMISSION
ENERGY RANGE
FLUIDS
GASES
INFORMATION
ION COLLISIONS
IONS
MEV RANGE
NONMETALS
NUMERICAL DATA
RARE GASES
640304* - Atomic
Molecular & Chemical Physics- Collision Phenomena