Relativistic distorted-wave cross sections for electron-impact excitations of berylliumlike ions

Journal Article · Mon May 01 00:00:00 EDT 1989 · Phys. Rev. A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.39.4509· OSTI ID:6167998

Qian, W; Kim, Y; Desclaux, J

Relativistic distorted-wave Born (RDWB) cross sections of Be-like ions for excitations from the ground state 2s/sup 2/ /sup 1/S/sub 0/ to the 2s2p /sup 3/P/sub 1/ and /sup 1/P/sub 1/ states by electron impact are reported for Ne/sup 6+/ through U/sup 88+/. Multiconfiguration Dirac-Fock wave functions were used to describe the target-ion states, and the relativistic continuum wave functions were calculated in the field of (frozen) target-ion charge distribution with the configuration-average exchange potential. We found, however, that cross sections hardly changed even if the exchange terms were omitted. In contrast, adding the 2p/sup 2/ configuration to the ground-state wave function reduced cross sections by 10--60 %. RDWB cross sections were calculated from thresholds to T = 10 keV, where T is the incident electron energy. For Zapprox. =25 and above, where Z is the nuclear charge, intermediate coupling mixes the /sup 3/P/sub 1/ and /sup 1/P/sub 1/ states such that the transition to the former becomes practically spin- and electric-dipole allowed, changing the high-T behavior of the excitation cross section. Cross sections are presented in compact fitting formulas that allow interpolations to determine cross sections with high precision for arbitrary Be-like ions (10less than or equal toZless than or equal to92) and arbitrary incident energies (Tless than or equal to10 keV).

• Research Organization: National Institute of Standards and Technology, Gaithersburg, Maryland 20899
• OSTI ID: 6167998
• Journal Information: Phys. Rev. A; (United States), Vol. 39:9
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ELECTRON-ION COLLISIONS
EXCITATION
CROSS SECTIONS
DWBA
ELECTRON CORRELATION
INTERMEDIATE COUPLING
ISOELECTRONIC ATOMS
THEORETICAL DATA
WAVE FUNCTIONS
ATOMS
BORN APPROXIMATION
COLLISIONS
CORRELATIONS
COUPLING
DATA
ELECTRON COLLISIONS
ENERGY-LEVEL TRANSITIONS
FUNCTIONS
INFORMATION
ION COLLISIONS
NUMERICAL DATA
640304* - Atomic
Molecular & Chemical Physics- Collision Phenomena