{
  "abstract": "The advent of X-ray free-electron lasers and high-harmonic generation has made time-resolved X-ray spectroscopy a powerful tool for probing local atomic environments, yet whether localized core excitations can report on global collective distortions remains open. Cyclo[18]carbon (C$_{18}$), with its polyynic ground state (D$_\\text{9h}$) and cumulenic transition state (D$_\\text{18h}$), provides an ideal model to address this long-standing issue in bond-length alternation (BLA) dynamics. Mapping two-dimensional potential energy surfaces by first-principles simulations, we find that core ionization symmetrizes the ground-state double-well potential along the BLA coordinate. Our calculated X-ray spectra reveal remarkable sensitivity to bond-length variations: C1s ionization potentials vary by up to 2.4~eV across the BLA coordinate (1.1--1.4~Å), with a 0.9~eV variation for minima predicted by different functionals, while NEXAFS $π^*$ peaks shift by up to 4~eV across the same coordinate. These predicted signatures provide a quantitative spectroscopy--structure dictionary for decoding transient structures in future ultrafast X-ray experiments and monitoring bond-alternation dynamics in real time.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.06916",
  "author_total": 7,
  "authors": [
    {
      "name": "Minrui Wei"
    },
    {
      "name": "Zeyu Liu"
    },
    {
      "name": "Sheng-Yu Wang"
    },
    {
      "name": "Jun-Rong Zhang"
    },
    {
      "name": "Lu Zhang"
    },
    {
      "name": "Guoyan Ge"
    },
    {
      "name": "Weijie Hua"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/drqhzxf9a9xse.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.06916",
  "fulltext_url": null,
  "id": "drqhzxf9a9xse",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.06916",
  "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",
      "physics.atm-clus"
    ],
    [
      "arxiv",
      "physics.chem-ph"
    ],
    [
      "arxiv",
      "physics.comp-ph"
    ],
    [
      "arxiv",
      "physics.optics"
    ],
    [
      "openalex",
      "3108|X-ray Spectroscopy and Fluorescence Analysis"
    ]
  ],
  "openalex": "W7212060885",
  "pdf_url": "https://arxiv.org/pdf/2609.06916",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-07",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/drqhzxf9a9xse.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:19:48Z",
      "native_id": "2609.06916",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.06916"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "arxiv:physics.chem-ph",
      "subfield": "physical"
    },
    {
      "field": "physics",
      "origin": "arxiv:physics.atm-clus",
      "subfield": "amo"
    },
    {
      "field": "physics",
      "origin": "arxiv:physics.comp-ph",
      "subfield": "computational"
    },
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mtrl-sci",
      "subfield": "condensed-matter"
    },
    {
      "field": "physics",
      "origin": "arxiv:physics.optics",
      "subfield": "optics-photonics"
    }
  ],
  "title": "Core-Level Spectroscopy Decodes Bond-Alternation Dynamics of Cyclo[18]Carbon",
  "title_text": "Core-Level Spectroscopy Decodes Bond-Alternation Dynamics of Cyclo[18]Carbon",
  "type": "preprint",
  "updated_at": "2026-10-30T12:19:48Z",
  "url": "https://research.draconitic.com/paper/drqhzxf9a9xse",
  "venue": "arXiv",
  "versions": []
}