Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: [O II] line ratios   Based on new calculations we reconfirm the low and high density limits on the
forbidden fine structure line ratio [O II] I(3729)/I(3726): lim_{N_ e} --> 0} =
1.5 and lim_{N_ e} --> \infty} = 0.35. Employing [O II] collision strengths
calculated using the Breit-Pauli R-matrix method we rule out any significant
deviation due to relativistic effects from these canonical values. The present
results are in substantial agreement with older calculations by Pradhan (1976)
and validate the extensive observational analysis of gaseous nebulae by Copetti
and Writzel (2002) and Wang et al (2004) that reach the same conclusions. The
present theoretical results and the recent observational analyses differ
significantly from the calculations by MacLaughlin and Bell (1998) and Keenan
et al (1999). The new maxwellian averaged effective collision strengths are
presented for the 10 transitions among the first 5 levels to enable
computations of [O II] line ratios.

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The categories of this paper are: math
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The categories of this paper are: math-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: adap-org
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The categories of this paper are: eess
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The categories of this paper are: nucl-th
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The categories of this paper are: gr-qc
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-ex
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The categories of this paper are: cond-mat
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The categories of this paper are: q-alg
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The categories of this paper are: dg-ga
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The categories of this paper are: q-bio
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The categories of this paper are: patt-sol
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The categories of this paper are: stat
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The categories of this paper are: hep-ph