Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Electronic Spectra of Ytterbium Fluoride from Relativistic Electronic
  Structure Calculations   We report an investigation of the low-lying excited states of the YbF
molecule--a candidate molecule for experimental measurements of the electron
electric dipole moment--with 2-component based multi-reference configuration
interaction (MRCI), equation of motion coupled cluster (EOM-CCSD) and the
extrapolated intermediate Hamiltonian Fock-space coupled cluster (XIHFS-CCSD).
Specifically, we address the question of the nature of these low-lying states
in terms of configurations containing filled or partially-filled Yb $4f$
shells. We show that while it does not appear possible to carry out
calculations with both kinds of configurations contained in the same active
space, reliable information can be extracted from different sectors of Fock
space--that is, by performing electron attachment and detachment IHFS-CCSD and
EOM-CCSD calculation on the closed-shell YbF$^+$ and YbF$^-$ species,
respectively. From these we observe $\Omega = 1/2, 3/2$ states that arise from
the $4f^{13}\sigma_{6s}^2$, $4f^{14}5d$/$6p$, and $4f^{13}5d\sigma_{6s}$
configurations appear in the same energy range around the ground-state
equilibrium geometry and they are therefore able to interact. As these states
are generated from different sectors of Fock space, they are almost orthogonal
and provide complementary descriptions of parts of the excited state manifold.
To obtain a comprehensive picture, we introduce a simple adiabatization model
to extract energies of interacting $\Omega = 1/2, 3/2$ states that can be
compared to experimental observations.

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The categories of this paper are: q-alg
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The categories of this paper are: hep-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: nucl-th
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The categories of this paper are: acc-phys
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The categories of this paper are: math-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: atom-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-lat
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The categories of this paper are: cmp-lg
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The categories of this paper are: chem-ph
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The categories of this paper are: q-bio
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The categories of this paper are: cond-mat
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The categories of this paper are: q-fin