Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: High-Frequency Electron-Spin-Resonance Study of the Octanuclear Ferric
  Wheel CsFe$_8$   High-frequency ($f$ = 190 GHz) electron paramagnetic resonance (EPR) at
magnetic fields up to 12 T as well as Q-band ($f$ = 34.1 GHz) EPR were
performed on single crystals of the molecular wheel CsFe$_8$. In this molecule,
eight Fe(III) ions, which are coupled by nearest-neighbor antiferromagnetic
(AF) Heisenberg exchange interactions, form a nearly perfect ring. The
angle-dependent EPR data allow for the accurate determination of the spin
Hamiltonian parameters of the lowest spin multiplets with $S \leq$ 4.
Furthermore, the data can well be reproduced by a dimer model with a uniaxial
anisotropy term, with only two free parameters $J$ and $D$. A fit to the dimer
model yields $J$ = -15(2) cm$^{-1}$ and $D$ = -0.3940(8) cm$^{-1}$. A rhombic
anisotropy term is found to be negligibly small, $E$ = 0.000(2) cm$^{-1}$. The
results are in excellent agreement with previous inelastic neutron scattering
(INS) and high-field torque measurements. They confirm that the CsFe$_8$
molecule is an excellent experimental model of an AF Heisenberg ring. These
findings are also important within the scope of further investigations on this
molecule such as the exploration of recently observed magnetoelastic
instabilities.

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The categories of this paper are: bayes-an
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The categories of this paper are: atom-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: chem-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: math-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: acc-phys
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The categories of this paper are: astro-ph
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The categories of this paper are: econ
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The categories of this paper are: q-bio
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The categories of this paper are: math
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The categories of this paper are: nlin
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The categories of this paper are: nucl-th