Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Near-exact CCSDT energetics from rank-reduced formalism supplemented by
  non-iterative corrections   We introduce a non-iterative energy correction, added on top of the
rank-reduced coupled-cluster method with single, double, and triple
substitutions, that accounts for excitations excluded from the parent triple
excitation subspace. The formula for the correction is derived by employing the
coupled-cluster Lagrangian formalism with an additional assumption that the
parent excitation subspace is closed under the action of the Fock operator.
Owning to the rank-reduced form of the triple excitation amplitudes tensor, the
computational cost of evaluating the correction scales as $N^7$ with the system
size, $N$. The accuracy and computational efficiency of the proposed method is
assessed both for total and relative correlation energies. We show that the
non-iterative correction can fulfill two separate roles. If an accuracy level
of a fraction of kJ/mol is sufficient for a given system the correction
significantly reduces the dimension of the parent triple excitation subspace
needed in the iterative part of the calculations. Simultaneously, it enables to
reproduce the exact CCSDT results to an accuracy level below 0.1 kJ/mol with a
larger, yet still reasonable, dimension of the parent excitation subspace. This
typically can be achieved at a computational cost only several times larger
than required for the CCSD(T) method. The proposed method retains black-box
features of the single-reference coupled-cluster theory; the dimension of the
parent excitation subspace remains the only additional parameter that has to be
specified.

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The categories of this paper are: q-bio
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The categories of this paper are: hep-lat
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The categories of this paper are: chao-dyn
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The categories of this paper are: chem-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: alg-geom
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The categories of this paper are: solv-int
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The categories of this paper are: eess
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-th
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The categories of this paper are: q-alg
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The categories of this paper are: patt-sol
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The categories of this paper are: cmp-lg
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The categories of this paper are: math
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The categories of this paper are: bayes-an
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The categories of this paper are: comp-gas