Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electronic Stopping of Slow Protons in Transition and Rare Earth Metals:
  Breakdown of the Free Electron Gas Concept   The electronic stopping cross sections (SCS) of Ta and Gd for slow protons
have been investigated experimentally. The data are compared to the results for
Pt and Au to learn how electronic stopping in transition and rare earth metals
correlates with features of the electronic band structures. The extraordinarily
high SCS observed for protons in Ta and Gd cannot be understood in terms of a
free electron gas model, but are related to the high densities of both occupied
and unoccupied electronic states in these metals.

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The categories of this paper are: q-alg
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The categories of this paper are: acc-phys
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The categories of this paper are: adap-org
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The categories of this paper are: bayes-an
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The categories of this paper are: alg-geom
10
The categories of this paper are: q-bio
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The categories of this paper are: nlin
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The categories of this paper are: eess
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The categories of this paper are: astro-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: chem-ph
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The categories of this paper are: hep-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
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The categories of this paper are: cmp-lg