Low-energy fine-structure resonances in photoionization of O ii

Journal Article · Wed Dec 15 00:00:00 EST 2010 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.82.065401· OSTI ID:21529009

Nahar, Sultana N; Pradhan, Anil K ^[1]; Montenegro, Maximiliano ^[2]; Eissner, Werner ^[3]

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1. Department of Astronomy, Ohio State University, Columbus, Ohio 43210 (United States)
2. Facultad de Educaci, Pontificia Universidad Catholica de Chile, Avda Vicua Mackenna 4860, Macul, Santiago (Chile)
3. Institut fuer Theoretische Physik, Teilinstitut 1, D-70550 Stuttgart (Germany)

Resonant features in low-energy photoionization cross sections are reported in coupled-channel calculations for O ii including relativistic fine structure. The calculations reveal extensive near-threshold resonant structures in the small energy region between the fine structure levels of the ground state 2p{sup 2}({sup 3}P{sub 0,1,2}) of the residual ion O iii. Although the resonances have not yet been observed, they are similar to other experimentally observed features. They are expected to significantly enhance the very-low-temperature dielectronic recombination rates, potentially leading to the resolution of an outstanding nebular abundances anomaly. Higher energy partial and total photoionization cross sections of the ground configuration levels 2p{sup 3}({sup 4}S{sub 3/2}{sup o},{sup 2}D{sub 3/2,5/2}{sup o},{sup 2}P{sub 1/2,3/2}{sup o}) are found to be in agreement with experimental measurements on synchrotron-based photon sources [1-3], thereby identifying the excited O iii levels present in the ion beams. These are also the first results from a recently developed version of Breit-Pauli R-matrix (BPRM) codes, with inclusion of two-body magnetic interaction terms. The improved relativistic treatment could be important for other astrophysical applications and for more precise benchmarking of experimental measurements.

• OSTI ID: 21529009
• Journal Information: Physical Review. A, Vol. 82, Issue 6; Other Information: DOI: 10.1103/PhysRevA.82.065401; (c) 2010 American Institute of Physics; ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
ABUNDANCE
ASTROPHYSICS
COUPLED CHANNEL THEORY
CROSS SECTIONS
FINE STRUCTURE
GROUND STATES
INTERACTIONS
ION BEAMS
PHOTOIONIZATION
PHOTONS
R MATRIX
RECOMBINATION
RELATIVISTIC RANGE
RESOLUTION
RESONANCE
SYNCHROTRONS
TEMPERATURE RANGE 0013-0065 K
TWO-BODY PROBLEM
ACCELERATORS
BEAMS
BOSONS
CYCLIC ACCELERATORS
ELEMENTARY PARTICLES
ENERGY LEVELS
ENERGY RANGE
IONIZATION
MANY-BODY PROBLEM
MASSLESS PARTICLES
MATRICES
PHYSICS
TEMPERATURE RANGE