Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Raman Scattering in the Inorganic Spin-Peierls System
  alpha'-Na_{1-delta}V_2O_5   We have studied the spin-Peierls (SP) transition in alpha'-Na_{1-delta}V_2O_5
(delta = 0, 0.01 and 0.1) by means of Raman scattering. At room temperature, we
observe six A_1 and three A_2 phonon modes and a broad Raman band. Below
T_{SP}several new peaks and a new broad band appear. The new peak at 62 cm^{-1}
originates from the SP-gap excitation. The new peak at 128 cm^{-1} and the new
broad band between 130 and 400 cm^{-1} come from two magnetic excitations. The
new peaks at 102, 646 and 944 cm^{-1} are assigned to the folded phonon modes
and their Na^+-ion deficiency dependence shows that the defect of Na^+ ion
suppresses the SPtransition. The polarized Raman spectra below T_{SP} suggest
that the possible crystal symmetry is C_s^2(Pn) or C_1^1(P1). The asymmetric
lineshape of the 531-cm^{-1} peak superimposed on the electronic Raman band
from the d-d transition around 600 cm^{-1} is interpreted in terms of the Fano
resonance between the electronic continuous band and the phonon with a finite
lifetime. The defects of the Na^+ ions reduce the Fano effect because the life
time of the phonon and the phonon-continuum interaction are decreased.

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The categories of this paper are: eess
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The categories of this paper are: q-bio
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The categories of this paper are: physics
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The categories of this paper are: stat
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The categories of this paper are: patt-sol
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The categories of this paper are: ao-sci
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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: cmp-lg
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The categories of this paper are: bayes-an
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The categories of this paper are: gr-qc
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The categories of this paper are: math
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The categories of this paper are: solv-int
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The categories of this paper are: adap-org
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The categories of this paper are: acc-phys
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The categories of this paper are: quant-ph