Indirect processes in electron impact ionization of Kr[sup 24+] and Kr[sup 25+]

Conference · Tue Sep 01 04:00:00 EDT 1992

OSTI ID:6521293

Chen, M H; Reed, K J

Electron-impact ionization cross sections have been calculated for magnesiumlike Kr[sup 24+] and sodiumlike Kr[sup 25+]. Electron-impact ionization is an important atomic process in hot dense plasmas. It can affect the ionization balance, electron temperature, electron density, and level population in the plasma. In the past decade, theoretical and experimental studies have revealed that indirect processes can make significant contributions to the cross sections for electron impact ionization of positive ions. The most important indirect process is excitation of an inner-shell electron followed by Auger emission. Higher-order processes such as resonant excitation followed by sequential double Auger emission, can also contribute significantly. The contributions of excitation-autoionization and resonant excitation double autoionization (REDA) were included, in addition to the cross sections for direct ionization of a 3s electron. The calculations were carried out using the relativistic distorted wave methods and the multiconfiguration Dirac-Fock model. For Kr[sup 25+], the total cross section is about 5 times the direct ionization cross section. For the Kr[sup 24+], the indirect contribution is about 2.5 times the direct ionization cross section. The REDA process produces many strong resonances and contributes about 20% to the average ionization cross section.

• Research Organization: Lawrence Livermore National Lab., CA (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6521293
• Report Number(s): UCRL-JC-111717; CONF-920948--13; ON: DE93014129
• Country of Publication: United States
• Language: English

Related Subjects

664300* -- Atomic & Molecular Physics-- Collision Phenomena-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
AUGER EFFECT
AUTOIONIZATION
CALCULATION METHODS
CHARGED PARTICLES
COLLISIONS
CROSS SECTIONS
DISTORTED WAVE THEORY
ELECTRON COLLISIONS
ELECTRON-ION COLLISIONS
ENERGY-LEVEL TRANSITIONS
EXCITATION
INNER-SHELL EXCITATION
ION COLLISIONS
IONIZATION
IONS
KRYPTON IONS