Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Atomic Data for Astrophysics. II. New Analytic Fits for Photoionization
  Cross Sections of Atoms and Ions   We present a complete set of analytic fits to the non-relativistic
photoionization cross sections for the ground states of atoms and ions of
elements from H through Si, and S, Ar, Ca, and Fe. Near the ionization
thresholds, the fits are based on the Opacity Project theoretical cross
sections interpolated and smoothed over resonances. At higher energies, the
fits reproduce calculated Hartree-Dirac-Slater photoionization cross sections.

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The categories of this paper are: hep-th
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The categories of this paper are: nlin
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The categories of this paper are: cs
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The categories of this paper are: hep-ex
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The categories of this paper are: hep-lat
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The categories of this paper are: q-bio
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The categories of this paper are: alg-geom
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The categories of this paper are: math
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The categories of this paper are: chao-dyn
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The categories of this paper are: acc-phys
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The categories of this paper are: quant-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: mtrl-th
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-ph
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The categories of this paper are: math-ph