Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Energy-dependence of skin-mode fraction in $E1$ excitations of
  neutron-rich nuclei   We have extensively investigated characters of the low-energy $E1$ strengths
in $N>Z$ nuclei, by analyzing the transition densities obtained by the HF+RPA
calculations with several effective interactions. Crossover behavior has been
confirmed, from the skin mode at low energy to the $pn$ mode at higher energy.
Decomposing the $E1$ strengths into the skin-mode, $pn$-mode and interference
fractions, we show that the ratio of the skin-mode strength to the full
strength may be regarded as a generic function of the excitation energy,
insensitive to nuclides and effective interactions, particularly beyond Ni.

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The categories of this paper are: q-bio
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The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
25
The categories of this paper are: patt-sol
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The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys
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The categories of this paper are: alg-geom
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The categories of this paper are: q-alg
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The categories of this paper are: stat
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The categories of this paper are: q-fin
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The categories of this paper are: physics
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The categories of this paper are: cond-mat
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The categories of this paper are: chem-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: econ
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The categories of this paper are: solv-int