Anisotropic radiative emission effects on deduced resonant-transfer-excitation cross sections

Journal Article · Mon Oct 01 04:00:00 EDT 1990 · Physical Review, A; (USA)

DOI:https://doi.org/10.1103/PhysRevA.42.3795· OSTI ID:6229703

Badnell, N R ^[1]

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1. Department of Physics, Auburn University, Auburn, Alabama 36849-5311 (USA)

The radiation emitted by an ion collisionally excited by an electron beam is anisotropic. We discuss two schemes, one for use with {ital LS}-coupling cross sections and one for intermediate coupling, whereby theoretical resonant-transfer-excitation cross sections can be modified to take account of this anisotropy when making comparisons with experimental results deduced from observations of radiation at a particular beam angle. We have carried out such calculations for a number of ions initially in an {ital S} state, viz. F{sup 6+}, Ca{sup {ital q}+} ({ital q}=16--19), and Nb{sup {ital q}+} ({ital q}=29--31). In all cases, neglecting hyperfine structure, the allowance for anisotropic radiative emission at right angles to the beam axis was found to result in only a small increase (10--15 %) in the cross section over results that assumed isotropy. Allowance for hyperfine structure reduced even this anisotropy by 20% for {sup 19}F{sup 6+} ({ital I}=1/2) and by 80% for {sup 93}Nb ({ital I}=9/2) ions; results for {sup 40}Ca ({ital I}=0) ions remain unchanged.

• DOE Contract Number: FG05-86ER53217
• OSTI ID: 6229703
• Journal Information: Physical Review, A; (USA), Journal Name: Physical Review, A; (USA) Vol. 42:7; ISSN 1050-2947; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ANISOTROPY
CALCIUM IONS
CHARGED PARTICLES
COLLISIONS
COUPLING
CROSS SECTIONS
E1-TRANSITIONS
ELECTRON COLLISIONS
ELECTRON-ION COLLISIONS
ENERGY-LEVEL TRANSITIONS
EXCITATION
FLUORINE IONS
INTERMEDIATE COUPLING
ION COLLISIONS
IONS
L-S COUPLING
MULTICHARGED IONS
MULTIPOLE TRANSITIONS
NIOBIUM IONS
RADIATIVE DECAY