{
  "abstract": "In this work, we implement closed-shell Brueckner orbitals for the efficient domain-based local pair natural orbital DLPNO-CCSD(T) and DLPNO-CCSD(T)$_Λ$ methods of the free and open-source \\textsc{Psi4} package. We introduce a new algorithm that allows Brueckner orbitals to be computed within the DLPNO framework, resulting in the novel DLPNO-BCCD(T) and DLPNO-BCCD(T)$_{Λ_2}$ methods. We show that DLPNO-BCCD(T) approximates its canonical BCCD(T) counterpart with significantly lower errors relative to the errors incurred by DLPNO-CCSD(T) over CCSD(T). Through a test on the S22 set of noncovalent dimers, the peak error across the set is reduced from 0.36 kcal mol$^{-1}$ to 0.25 kcal mol$^{-1}$ using normal cutoffs, and 0.28 kcal mol$^{-1}$ to 0.13 kcal mol$^{-1}$ at tight cutoffs. In addition, we show that BCCD(T)$_{Λ_2}$, a ${Λ_2}$-only implementation of Brueckner orbitals for the asymmetric triples method, generally produces the best agreement with CCSDT, compared to the (T), (T)$_Λ$, and B(T) perturbative triples corrections. This is established through benchmarks on thermochemistry tests on the barrier heights of semibullvalene and bullvalene Cope rearrangement, while the robustness of DLPNO-BCCD(T)$_{Λ_2}$ is demonstrated along bond-breaking potential energy curves, where it matches the orbital-optimized quasi-variational asymmetric renormalized-triples OQVCCDAR(T) method closely for single-bond breaking, and approximates DLPNO-CCSDT respectably even when triple bonds are stretched, at a fraction of the computational cost.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2611.06600",
  "author_total": 5,
  "authors": [
    {
      "name": "Andy Jiang"
    },
    {
      "name": "Tibor Gyori"
    },
    {
      "name": "Elizabeth C. Toth"
    },
    {
      "name": "Gabor Czako"
    },
    {
      "name": "Henry F. Schaefer III"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/7cacnsyk1ps24.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2611.06600",
  "fulltext_url": null,
  "id": "7cacnsyk1ps24",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2611.06600",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "physics.chem-ph"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2611.06600",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-04",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/7cacnsyk1ps24.ris",
  "sources": [
    {
      "first_seen": "2026-11-05T15:20:56Z",
      "native_id": "2611.06600",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2611.06600"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "arxiv:physics.chem-ph",
      "subfield": "physical"
    }
  ],
  "title": "Brueckner Orbitals in Local Pair Natural Orbital Coupled-Cluster Theory: DLPNO-BCCD(T) and DLPNO-BCCD(T)_Lambda2",
  "title_text": "Brueckner Orbitals in Local Pair Natural Orbital Coupled-Cluster Theory: DLPNO-BCCD(T) and DLPNO-BCCD(T)_Lambda2",
  "type": "preprint",
  "updated_at": "2026-11-09T00:20:20Z",
  "url": "https://research.draconitic.com/paper/7cacnsyk1ps24",
  "venue": "arXiv",
  "versions": []
}