Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Symmetry properties of vibrational modes in graphene nanoribbons   We present symmetry properties of the lattice vibrations of graphene
nanoribbons with pure armchair (AGNR) and zigzag edges (ZGNR). In
non-symmorphic nanoribbons the phonon modes at the edge of the Brillouin zone
are twofold degenerate, whereas the phonon modes in symmorphic nanoribbons are
non-degenerate. We identified the Raman-active and infrared-active modes. We
predict 3N and 3(N+1) Raman-active modes for N-ZGNRs and N-AGNRs, respectively
(N is the number of dimers per unit cell). These modes can be used for the
experimental characterization of graphene nanoribbons. Calculations based on
density functional theory suggest that the frequency splitting of the LO and TO
in AGNRs (corresponding to the E2g mode in graphene) exhibits characteristic
width and family dependence. Further, all graphene nanoribbons have a
Raman-active breathing-like mode, the frequency of which is inversely
proportional to the nanoribbon width and thus might be used for experimental
determination of the width of graphene nanoribbons.

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The categories of this paper are: chem-ph
1
The categories of this paper are: cs
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The categories of this paper are: dg-ga
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The categories of this paper are: supr-con
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The categories of this paper are: econ
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The categories of this paper are: acc-phys
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The categories of this paper are: q-alg
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The categories of this paper are: gr-qc
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The categories of this paper are: plasm-ph
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The categories of this paper are: math
8
The categories of this paper are: hep-ex
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The categories of this paper are: hep-th
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-lat
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The categories of this paper are: ao-sci
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The categories of this paper are: eess