{
  "abstract": "Open-shell $3d$ transition-metal complexes pose a stringent challenge for correlated electronic-structure methods because near-degenerate metal $d$ orbitals give rise to competing spin states and oxidation-state-dependent charge transfer, while solvation can reshape the relative stability of the resulting electronic configurations. Building on prior demonstrations of open-shell sample-based quantum diagonalization (SQD) for light-atom systems and, separately, closed-shell SQD coupled to the integral-equation-formalism polarizable continuum model (IEF-PCM), we combine these capabilities through an open-shell SQD--IEF-PCM framework and apply it to the octahedrally coordinated $\\mathrm{[Co(H_2O)_5CO_2]^{2+/3+}}$ complex, spanning the Co(III) singlet and quintet and Co(II) doublet and quartet states along a metal--ligand dissociation coordinate. Using quantum samples collected on an IBM Heron processor and active spaces of up to 50 qubits, SQD closely reproduces coupled-cluster and heat-bath configuration-interaction benchmarks within the same active spaces in both gas phase and implicit solvent; for high-spin quintet $\\mathrm{[Co(H_2O)_5CO_2]^{3+}}$, it additionally resolves an avoided crossing associated with internal charge transfer that is absent in the corresponding singlet and in the lower oxidation state, while IEF-PCM suppresses this crossover by preferentially stabilizing the dissociation channel leading to neutral CO$_2$. To our knowledge, this work provides the first hardware demonstration of SQD for an open-shell 3d transition-metal complex with discrete metal-centered d-orbital chemistry, and the first application of open-shell SQD in a dielectric continuum, establishing a quantum-centric framework for transition-metal chemistry in regimes where spin-state energetics, charge transfer, and environmental response are strongly coupled.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2607.16389",
  "author_total": 8,
  "authors": [
    {
      "name": "David David"
    },
    {
      "name": "Vedangi Pathak"
    },
    {
      "name": "Marek Kowalik"
    },
    {
      "name": "Hamed Mohammadbagherpoor"
    },
    {
      "name": "Vincent Beltrani"
    },
    {
      "name": "Kara Maller"
    },
    {
      "name": "Niall Moroney"
    },
    {
      "name": "Phalgun Lolur"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/1wmp6ka5zrmf4.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2607.16389",
  "fulltext_url": null,
  "id": "1wmp6ka5zrmf4",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2607.16389",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "quant-ph"
    ],
    [
      "openalex",
      "3107|Advanced Chemical Physics Studies"
    ]
  ],
  "openalex": "W7169829233",
  "pdf_url": "https://arxiv.org/pdf/2607.16389",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-29",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/1wmp6ka5zrmf4.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:25:31Z",
      "native_id": "2607.16389",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2607.16389"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:quant-ph",
      "subfield": "quantum"
    }
  ],
  "title": "Sample-based quantum diagonalization approach for open-shell transition-metal complexes in gas and implicit-solvent",
  "title_text": "Sample-based quantum diagonalization approach for open-shell transition-metal complexes in gas and implicit-solvent",
  "type": "preprint",
  "updated_at": "2026-10-30T12:25:31Z",
  "url": "https://research.draconitic.com/paper/1wmp6ka5zrmf4",
  "venue": "arXiv",
  "versions": []
}