Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Direct observation of the M1 transition between the ground state fine
  structure splitting of W VIII   We present direct observation of the M1 transition between the fine structure
splitting in the 4f13 5s2 5p6 2F ground state of W VIII. The spectroscopic data
of few-times ionized tungsten ions are important for the future ITER
diagnostics, but there is a serious lack of data. The present study is part of
an ongoing effort to solve this lack. Emission from the tungsten ions produced
and trapped in a compact electron beam ion trap is observed with a
Czerny-Turner visible spectrometer. Spectra in the EUV range are also observed
at the same time to help the identification of the previously-unreported
visible lines. The observed wavelength 574.47 pm 0.03 nm (air), which
corresponds to the fine structure splitting of 17402.5 pm 0.9 cm-1, shows
reasonable agreement with the previously reported value 17410 pm 5 cm-1
obtained indirectly through the analysis of EUV spectra [Ryabtsev et al., Atoms
3 (2015) 273].

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The categories of this paper are: q-bio
1
The categories of this paper are: cs
24
The categories of this paper are: dg-ga
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The categories of this paper are: nucl-th
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The categories of this paper are: atom-ph
11
The categories of this paper are: hep-lat
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The categories of this paper are: q-alg
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The categories of this paper are: nucl-ex
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The categories of this paper are: cmp-lg
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The categories of this paper are: solv-int
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The categories of this paper are: eess
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The categories of this paper are: adap-org
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The categories of this paper are: math-ph
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The categories of this paper are: econ
33
The categories of this paper are: plasm-ph
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The categories of this paper are: gr-qc