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Title: Autoionizing resonances in electron-impact excitation of oxygenlike selenium

We have investigated the contributions of doubly excited, autoionizing resonances to the rate coefficients for electron-impact excitation of the n = 2 to n = 2 transitions in oxygenlike selenium. The cross sections for direct excitation were calculated using a relativistic distorted-wave approximation. The detailed Auger and radiative rates required for evaluating the resonance contributions were calculated using a multiconfigurational Dirac-Fock model. The largest effect is on the electric-dipole-forbidden transitions. For some J = 0 to J = 0 transitions involving two-electron excitations, the resonances enhance the collisional excitation rates by factors up to 10/sup 4/ at electron temperatures relevant for laboratory plasmas.
Authors:
; ;
Publication Date:
OSTI Identifier:
7065546
Resource Type:
Journal Article
Resource Relation:
Journal Name: Phys. Rev. A; (United States); Journal Volume: 38:7
Research Org:
High Temperature Physics Division, Lawrence Livermore National Laboratory, Livermore, California 94550
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; SELENIUM IONS; AUTOIONIZATION; CROSS SECTIONS; DISTORTED WAVE THEORY; ELECTRON-ION COLLISIONS; EXCITATION; RESONANCE; AUGMENTATION; ISOELECTRONIC ATOMS; KINETICS; OXYGEN; PLASMA; USES; ATOMS; CHARGED PARTICLES; COLLISIONS; ELECTRON COLLISIONS; ELEMENTS; ENERGY-LEVEL TRANSITIONS; ION COLLISIONS; IONIZATION; IONS; NONMETALS 640304* -- Atomic, Molecular & Chemical Physics-- Collision Phenomena