Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Multireference Algebraic Diagrammatic Construction Theory for Excited
  States: Extended Second-Order Implementation and Benchmark   We present an implementation and benchmark of new approximations in
multireference algebraic diagrammatic construction theory for simulations of
neutral electronic excitations and UV/Vis spectra of strongly correlated
molecular systems (MR-ADC). Following our work on the first-order MR-ADC
approximation [J. Chem. Phys. 2018, 149, 204113], we report the strict and
extended second-order MR-ADC methods (MR-ADC(2) and MR-ADC(2)-X) that combine
the description of static and dynamic electron correlation in the ground and
excited electronic states without relying on state-averaged reference
wavefunctions. We present an extensive benchmark of the new MR-ADC methods for
excited states in several small molecules, including the carbon dimer,
ethylene, and butadiene. Our results demonstrate that for weakly-correlated
electronic states the MR-ADC(2) and MR-ADC(2)-X methods outperform the
third-order single-reference ADC approximation and are competitive with the
results from equation-of-motion coupled cluster theory. For states with
multireference character, the performance of the MR-ADC methods is similar to
that of an N-electron valence perturbation theory. In contrast to conventional
multireference perturbation theories, the MR-ADC methods have a number of
attractive features, such as a straightforward and efficient calculation of
excited-state properties and a direct access to excitations outside of the
frontier (active) orbitals.

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The categories of this paper are: q-bio
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The categories of this paper are: bayes-an
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The categories of this paper are: comp-gas
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The categories of this paper are: econ
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The categories of this paper are: nucl-ex
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The categories of this paper are: patt-sol
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The categories of this paper are: astro-ph
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The categories of this paper are: stat
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The categories of this paper are: hep-lat
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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: atom-ph
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The categories of this paper are: hep-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: ao-sci
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The categories of this paper are: cond-mat