{
  "abstract": "Anion redox in Li-rich layered oxides places holes on oxygen next to an antiferromagnetic Mn(IV) d3 lattice, a strongly correlated open-shell problem for which projection-based wavefunction-in-DFT embedding offers a route to correlated and quantum solvers, but whose errors are known mainly for closed-shell molecules. We develop a spin-unrestricted projection-based embedding, exact at the DFT-in-DFT level to the microhartree scale for closed-shell, broken-symmetry and high-spin references with point charges, and apply DMRG-in-DFT to point-charge clusters of delithiated Li(2-x)MnO3, varying the environment functional (0-100% exact exchange), geometry, active region, active-space spin, virtual space, cluster size and magnetic reference. In every setting the lowest SCF state places the hole on an oxygen pair, with no O-O bond. How the hole is shared depends on the functional together with the geometry: hybrids give a full, uncoupled hole at the DFT+U geometry but a partial, weakly covalent hole at their own geometry, a change of up to 0.5 e on one oxygen. Where spin spreads across the active/environment boundary, the integer spin projection of the active space becomes a choice worth up to 0.26 e, and at most 0.09 e once the two Mn neighbors are included. An extended state search found missed lower states for two functionals, changing a pair-oxygen spin by up to 0.45 e. Across all 82 runs the embedded mean field gives the same hole (median DMRG change 0.02-0.04 e); correlation mainly adds O-O covalency. State control and geometry consistency, not the solver, dominate the uncertainty, and total energies are not converged at 30-40 orbitals. For quantum solvers, the embedded Hamiltonian must be spin-unrestricted: a shared-orbital form reverses the hole, while sample-based quantum diagonalization reproduces exact diagonalization, as accurately as, but not better than, classical selected CI.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.36659",
  "author_total": 3,
  "authors": [
    {
      "name": "Pritam Das"
    },
    {
      "name": "Satadeep Bhattacharjee"
    },
    {
      "name": "Pil-Ryung Cha"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/dy2m9r7cm3yn7.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.36659",
  "fulltext_url": null,
  "id": "dy2m9r7cm3yn7",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.36659",
  "language": null,
  "licence": "CC-BY-NC-ND-4.0",
  "licence_label": "CC BY-NC-ND 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "cond-mat.mtrl-sci"
    ],
    [
      "arxiv",
      "cond-mat.str-el"
    ],
    [
      "arxiv",
      "physics.chem-ph"
    ],
    [
      "openalex",
      "3107|Advanced Chemical Physics Studies"
    ]
  ],
  "openalex": "W7224103604",
  "pdf_url": "https://arxiv.org/pdf/2610.36659",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-27",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/dy2m9r7cm3yn7.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:35:50Z",
      "native_id": "2610.36659",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.36659"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "arxiv:physics.chem-ph",
      "subfield": "physical"
    },
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mtrl-sci",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Where Does the Anion-Redox Hole Go? Reliability of Open-Shell Projection-Based Embedding for Li-Rich Cathodes, from DFT Environments to Quantum Solvers",
  "title_text": "Where Does the Anion-Redox Hole Go? Reliability of Open-Shell Projection-Based Embedding for Li-Rich Cathodes, from DFT Environments to Quantum Solvers",
  "type": "preprint",
  "updated_at": "2026-11-04T15:20:50Z",
  "url": "https://research.draconitic.com/paper/dy2m9r7cm3yn7",
  "venue": "arXiv",
  "versions": []
}