{
  "abstract": "In this work, we present a systematic investigation of the ground- and excited-states of six anionic sulfonated azo dyes with broad applications in the textile industry: Allura Red, Amaranth, Carmoisine, Ponceau, Red 2G, and Sunset Yellow. Ground-state properties were evaluated using density functional theory (DFT) at the $\\omega$B97X-D4/ma-def2-SVP level of theory. To identify the most suitable functional for excited-state calculations and to assess vertical excitation energies to low-lying excited-states, we tested a series of hybrid, meta-hybrid, and range-separated hybrid functionals from Jacob's ladder using the Tamm-Dancoff approximation (TDA) and the ma-def2-SVP basis set and compared to results from RI-CC2 and STEOM-DLPNO-CCSD approaches. excited-state properties were then further examined using TDA at the CAM-B3LYP//$\\omega$B97X-D4/ma-def2-SVP level of theory. Additionally, the quantum theory of atoms in molecules (QTAIM) was applied to explore density-related properties in both ground and excited-states. We found, perhaps not surprisingly, that excitation weakens the \\ce{N=N} bond in both the enol and keto forms of the dyes, but with variations depending on the molecule, conformer, and electronic state.",
  "abstract_shown": true,
  "affiliations": [
    "University of Alberta",
    "Universidade Federal de São Carlos"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 5,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Rodrigo Araujo Mendes",
      "orcid": "0000-0002-0279-4831"
    },
    {
      "affs": [
        0
      ],
      "name": "Victor A. S. da Mata"
    },
    {
      "affs": [
        0
      ],
      "name": "Ismael A. Elayan"
    },
    {
      "affs": [
        0
      ],
      "name": "Alex Brown"
    },
    {
      "affs": [
        1
      ],
      "name": "Gabriel L. C. de Souza"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/26ybpmfy3ac5g.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv-2025-rfk58/v2",
  "fulltext_url": null,
  "id": "26ybpmfy3ac5g",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv-2025-rfk58/v2",
  "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": "W7223286927",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv-2025-rfk58/v2",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-22",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/26ybpmfy3ac5g.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:26Z",
      "native_id": "10.26434/chemrxiv-2025-rfk58",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv-2025-rfk58/v2"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "openalex:3107|Advanced Chemical Physics Studies",
      "subfield": "amo"
    }
  ],
  "title": "Conformational and Tautomeric Effects on the excited-states of Sulfonated Azo Dyes",
  "title_text": "Conformational and Tautomeric Effects on the excited-states of Sulfonated Azo Dyes",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:26Z",
  "url": "https://research.draconitic.com/paper/26ybpmfy3ac5g",
  "venue": "ChemRxiv",
  "versions": []
}