{
  "abstract": "Time-resolved X-ray absorption spectroscopy (TR-XAS) offers an element- and site-specific probe of coupled electronic and nuclear dynamics, but its interpretation requires methods that can treat multiconfigurational excited states across nonequilibrium nuclear ensembles. Here, we report time-resolved simulations of the acetylacetone (AcAc) transient X-ray absorption spectra by combining surface-hopping dynamics from complete active space second-order perturbation theory with multireference algebraic diagrammatic construction (MR-ADC). The simulated 20-200 fs spectra show a good agreement with experimental measurements and reveal that the TR-XAS response is governed by continuously evolving distributions of molecular geometries on the singlet potential energy surfaces (S2 and S1). In particular, absorption at 279.5-281.5 eV is enhanced for transient, nearly symmetric proton-sharing configurations, whereas the 284-286 eV profile reflects geometry-dependent C1s excitations modulated by proton transfer, bond alternation, and ring opening. For the long-time T_1 spectrum (7-10 ps), the principal features near 281.4 and 283.8 eV are assigned to central C 1s excitations into low-lying triplet pi-orbitals. Together, our simulations provide a more complete mechanistic picture of AcAc photorelaxation by directly linking ultrafast carbon K-edge signals to proton transfer, skeletal reorganization, internal conversion, and triplet formation.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2608.09747",
  "author_total": 4,
  "authors": [
    {
      "name": "Bennett W. Clark"
    },
    {
      "name": "Donna H. Odhiambo"
    },
    {
      "name": "Haden Dickerson"
    },
    {
      "name": "Alexander Yu. Sokolov"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/7ed1egrgrexpd.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2608.09747",
  "fulltext_url": null,
  "id": "7ed1egrgrexpd",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2608.09747",
  "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",
      "physics.chem-ph"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2608.09747",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-19",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/7ed1egrgrexpd.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:34:04Z",
      "native_id": "2608.09747",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2608.09747"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "arxiv:physics.chem-ph",
      "subfield": "physical"
    }
  ],
  "title": "Decoding Transient X-ray Absorption Spectra of Acetylacetone With Multireference Algebraic Diagrammatic Construction Theory",
  "title_text": "Decoding Transient X-ray Absorption Spectra of Acetylacetone With Multireference Algebraic Diagrammatic Construction Theory",
  "type": "preprint",
  "updated_at": "2026-10-30T12:34:04Z",
  "url": "https://research.draconitic.com/paper/7ed1egrgrexpd",
  "venue": "arXiv",
  "versions": []
}