{
  "abstract": "Molecules strongly coupled to optical cavities often show multi-configurational character, which the cavity can enhance by mixing electronic states. Describing them accurately requires a complete treatment of correlation between all the involved quantum particles. The available QED ab-initio methods do not treat it in its completeness except for QED-FCI. We extend second-order N-electron valence state perturbation theory (NEVPT2) to polaritonic chemistry, in its state-specific (QED-NEVPT2) and quasi degenerate (QED-QD-NEVPT2) forms. Here, the correlation due to the interaction of more degenerate configurations comes from a QED-CASSCF reference, while that associated with instantaneous interactions between the particles is added by second-order perturbation theory. Application of the methods to ammonia, ethylene and formaldimine revealed that this approach represents the perfect alternative to the well established QED-Coupled Cluster approach when the molecular system is described by more degenerate configurations. The approaches developed in this work have the potential to become state-of-the-art methodologies for the description of reactivity and photochemistry in polaritonic systems.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.34416",
  "author_total": 4,
  "authors": [
    {
      "name": "Edoardo Ascani"
    },
    {
      "name": "Riccardo Alessandro"
    },
    {
      "name": "Celestino Angeli"
    },
    {
      "name": "Enrico Ronca"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/8220gkds214tr.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.34416",
  "fulltext_url": null,
  "id": "8220gkds214tr",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.34416",
  "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",
      "3107|Strong Light-Matter Interactions"
    ]
  ],
  "openalex": "W7223877545",
  "pdf_url": "https://arxiv.org/pdf/2610.34416",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-25",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/8220gkds214tr.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:35:35Z",
      "native_id": "2610.34416",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.34416"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "arxiv:physics.chem-ph",
      "subfield": "physical"
    }
  ],
  "title": "Second order N-Electron Valence state Perturbation Theory for polaritonic systems",
  "title_text": "Second order N-Electron Valence state Perturbation Theory for polaritonic systems",
  "type": "preprint",
  "updated_at": "2026-10-30T12:35:35Z",
  "url": "https://research.draconitic.com/paper/8220gkds214tr",
  "venue": "arXiv",
  "versions": []
}