Bethe cross sections for the sodium isoelectronic sequence
Bethe cross sections for the excitation of Na-like ions to the 3 /sup 2/P/sub 1/2/, 3 /sup 2/P/sub 3/2/, 4 /sup 2/P/sub 1/2/, and 4 /sup 2/P/sub 3/2/ states from the ground state are computed from the relativistic Hartree-Fock wave functions. As the nuclear charge is increased, excitation cross sections to the /sup 2/P/sub 3/2/ states are affected far more by relativistic effects than those to the /sup 2/P/sub 1/2/ states. The asymptotic ionization cross sections for the neutral Na atom and Fe/sup 15 +/ ion are computed from a sum rule, i.e., by subtracting the sum of discrete excitation cross sections from the total inelastic-scattering cross section obtained from the sum rule. The ionization cross sections thus obtained are sigma/sub ion/(Na) = ..beta../sup -2/(2.51)ln(..beta../sup 2//(1-..beta../sup 2/)) - ..beta../sup 2/) + 26.3) x 10/sup -20/ cm/sup 2/, sigma/sub ion/(Fe/sup 15 +/) = ..beta../sup -2/(0.209 )ln(..beta../sup 2//(1-..beta../sup 2/)) - ..beta../sup 2/) + 1.64) x 10/sup -20/ cm/sup 2/, where ..beta.. is the incident electron or proton speed divided by that of light. The cross section for Na is in agreement with that calculated by McGuire, but not with the electron-impact experiment by McFarland and Kinney. The ionization cross section for Fe/sup 15 +/ is a factor of 2 to 3 larger than the Coulomb-Born results by Rudge and Schwartz and by Bely in the asymptotic region.
- Research Organization:
- Argonne National Laboratory, Argonne, Illinois 60439
- OSTI ID:
- 6714301
- Journal Information:
- Phys. Rev., A; (United States), Journal Name: Phys. Rev., A; (United States) Vol. 18:1; ISSN PLRAA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ALKALI METALS
ATOMIC IONS
ATOMS
CHARGED PARTICLES
COLLISIONS
ELECTRON COLLISIONS
ELECTRON-ION COLLISIONS
ELEMENTS
ENERGY-LEVEL TRANSITIONS
EXCITATION
FIELD THEORIES
GENERAL RELATIVITY THEORY
HARTREE-FOCK METHOD
ION COLLISIONS
IONIZATION
IONS
ISOELECTRONIC ATOMS
METALS
MULTICHARGED IONS
RELATIVITY THEORY
SODIUM