Measurement of the radiative decay rate and energy of the metastable (2s{sup 2}2p{sub 1/2}{sup 5}3s{sub 1/2}){sub (J=0)} level in Fe xvii

Journal Article · Wed Jan 20 00:00:00 EST 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/817/1/67· OSTI ID:22887111

Beiersdorfer, P.; López-Urrutia, J. R. Crespo; Träbert, E. ^[1]

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1. Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 (United States)

Measurements at the Livermore electron beam ion trap have been performed in order to infer the energy and the radiative lifetime of the (1s{sup 2}2s{sup 2}2p{sub 1/2}{sup 5}3s{sub 1/2}){sub J=0} level in the Fe xvii spectrum. This is the longest-lived level in the neonlike iron ion, and its radiative decay produces the Fe xvii line at 1153 Å, feeding the population of the (1s{sup 2}2s{sup 2}2p{sub 3/2}{sup 5}3s{sub 1/2}){sub J=1} upper level of one of the most prominent lines in the Fe xvii L-shell X-ray spectrum, commonly dubbed 3G. In the presence of a strong (⩾ few kG) magnetic field, the (1s{sup 2}2s{sup 2}2p{sub 1/2}{sup 5}3s{sub 1/2}){sub J=0} level has a finite probability to decay directly to the (1s{sup 2}2s{sup 2}2p{sup 6}){sub J=0} neonlike ground level via the emission of an L-shell X-ray. Our measurements allow us to observe this X-ray line in the Fe xvii L-shell spectrum and from it to infer the radiative rate for the magnetic dipole decay of the (1s{sup 2}2s{sup 2}2p{sub 1/2}{sup 5}3s{sub 1/2}){sub J=0} level to the (1s{sup 2}2s{sup 2}2p{sub 3/2}{sup 5}3s{sub 1/2}){sub J=1}. Our result of (1.45±0.15)×10{sup 4} s{sup −1} is in agreement with predictions. We have also measured the wavelength of the associated X-ray line to be 16.804 ± 0.002 Å, which means that the line is displaced 1.20 ± 0.05 eV from the neighboring (2s{sup 2}2p{sub 1/2}{sup 5}3s{sub 1/2}){sub J=1}→(2s{sup 2}2p{sup 6}){sub J=0} transition, commonly labeled 3F. From our measurement, we infer 5950570 ± 710 cm{sup −1} for the energy of the (1s{sup 2}2s{sup 2}2p{sub 1/2}{sup 5}3s{sub 1/2}){sub J=0} level.

• OSTI ID: 22887111
• Journal Information: Astrophysical Journal, Vol. 817, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); Since 2009, the country of publication for this journal is the UK.; ISSN 0004-637X
• Country of Publication: United Kingdom
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
EMISSION
GROUND LEVEL
IRON IONS
L SHELL
MAGNETIC DIPOLES
MAGNETIC FIELDS
METASTABLE STATES
RADIATIVE DECAY
X-RAY SPECTRA