Distorted-wave theory of electron-ion collisions. II. Auger ionization and excitation fluorescence

Journal Article · Fri Sep 01 04:00:00 EDT 1978 · Phys. Rev., A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.18.1028· OSTI ID:6682178

Hahn, Y

When electrons of moderately high energy collide with multiply stripped ionic targets, the predominant mode of collision is the impact excitation of outer-shell electrons, which subsequently decay by radiative emission. As the degree of ionization increases, the strength for inner-shell excitation becomes comparable with that for the direct-impact ionization of outer-shell electrons. The inner-shell vacancy thus created may decay by emission of an electron (Auger ionization (AI)) or a photon (excitation fluorescence (EF)). For highly charged ionic targets, it is shown that the Auger ionization contributes significantly to the total ionization cross section, and becomes dominant over the direct-impact ionization in some cases (Mo/sup 24 +/). The excitation probabilities, both to discrete and continuum states, have been calculated for the inner- and outer-shell electrons, using the improved Bethe approximation and the semiclassical projection operator. The result shows the drastic decrease in the relative transition strength to the continuum as the degree of ionization Z/sub I/ increases. The branching ratios for the Auger ionization and fluorescence decay are fitted as functions of Z/sub I/ for ionized targets. The AI and EF cross sections are compared with the corresponding direct processes.

• Research Organization: Department of Physics, University of Connecticut, Storrs, Connecticut 06268
• OSTI ID: 6682178
• Journal Information: Phys. Rev., A; (United States), Journal Name: Phys. Rev., A; (United States) Vol. 18:3; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
AUGER EFFECT
BEAMS
BRANCHING RATIO
COLLISIONS
ELECTRON COLLISIONS
ELECTRON-ION COLLISIONS
ENERGY-LEVEL TRANSITIONS
EXCITATION
FLUORESCENCE
ION BEAMS
ION COLLISIONS
IONIZATION
LUMINESCENCE