{
  "abstract": "Double-hybrid density functional theory (DH-DFT) has emerged as the most accurate DFT for molecular thermochemistry and kinetics, yet its widespread adoption for molecules with many atoms, A, is restricted by the steep O(A5) computational scaling and large O(A3) memory footprint of conventional canonical basis second-order Møller–Plesset (MP2) perturbation theory. Our previously reported spin-restricted local MP2 framework based on numerical sparsity successfully eliminated the O(A5) scaling bottleneck of MP2 for closed-shell systems. In this work, we address the challenge of generalizing it to achieve a linear-scaling, spin-unrestricted local MP2 algorithm, which enables asymptotically linear scaling evaluation of double hybrids for open shell and reactive molecules. The O(A1) linear scaling wall time of our implementation is validated on model radical-cation chains. Shared-memory (OpenMP) and distributed-memory (MPI) parallel implementations are benchmarked on open-shell transition metal configurations from the ROST61, MME55 and 16OSTM10 datasets. Governed by a single, user-defined precision threshold (ϵ), the numerical sparsity algorithm recovers over 99.99% of the canonical correlation energy using ϵ = 10−6 (a reasonable choice for production calculations), and yields relative energies with root-mean-square errors well below the threshold of chemical accuracy. As a larger example, a 181-atom transition metal complex is evaluated in the large def2-QZVPP basis set (8, 792 basis functions) with ϵ = 10−6 within one day utilizing 128 MPI ranks. Finally, integration with different double hybrid functionals, including ωB97M(2), PBE-QIDH and revDSD-PBEP86-D4, is demonstrated.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Chemistry",
    "California",
    "Chemical Sciences Division",
    "Lawrence Berkeley National Laboratory",
    "Applied Mathematics and Computational Research Division"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 9,
  "authors": [
    {
      "affs": [
        0,
        1,
        2,
        3
      ],
      "name": "Yao Shen"
    },
    {
      "affs": [
        0,
        1,
        2,
        3
      ],
      "name": "Zhenling Wang"
    },
    {
      "affs": [
        4,
        3
      ],
      "name": "Tianyi Shi"
    },
    {
      "affs": [
        0,
        1,
        2,
        3
      ],
      "name": "Zhe Wang"
    },
    {
      "affs": [
        0,
        1,
        2,
        3
      ],
      "name": "Hrishikesh Ram"
    },
    {
      "affs": [
        0,
        1,
        2,
        3
      ],
      "name": "Etienne Palos"
    },
    {
      "affs": [
        4,
        3
      ],
      "name": "Yang Liu"
    },
    {
      "affs": [
        4,
        3
      ],
      "name": "Xiaoye S. Li"
    },
    {
      "affs": [
        0,
        1,
        2,
        3
      ],
      "name": "Martin Head-Gordon"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/e4vts3zz2y6hk.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15008144/v1",
  "fulltext_url": null,
  "id": "e4vts3zz2y6hk",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008144/v1",
  "language": null,
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "3107|Advanced Chemical Physics Studies"
    ]
  ],
  "openalex": "W7204918270",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15008144/v1",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-01",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/e4vts3zz2y6hk.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:17Z",
      "native_id": "10.26434/chemrxiv.15008144",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008144/v1"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "openalex:3107|Advanced Chemical Physics Studies",
      "subfield": "amo"
    }
  ],
  "title": "High precision, fast computation and high accuracy? Linear scaling double hybrid DFT calculations with spin-polarization",
  "title_text": "High precision, fast computation and high accuracy? Linear scaling double hybrid DFT calculations with spin-polarization",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:17Z",
  "url": "https://research.draconitic.com/paper/e4vts3zz2y6hk",
  "venue": "ChemRxiv",
  "versions": []
}