{
  "abstract": "Ultrafast electron diffraction (UED) provides direct information on changes in molecular structure following photoexcitation, but identifying the individual vibrational motions contributing to these dynamics remains challenging. Here, we introduce frequency-resolved UED, where Fourier transformation of the time-dependent difference pair distribution function ($Δ$PDF) gives a two-dimensional frequency-distance representation of the structural dynamics. We apply this approach to allene and 1,2-butadiene following photoexcitation to the $S_1(ππ^*)$ state at 200 nm, using electron scattering signals simulated from previously-published ab initio multiple spawning trajectories (S. P. Neville et al., J. Chem. Phys., 2016, 144, 014305). We identify C=C stretching and CCC bending motions and the internuclear distances over which they contribute, and separate overlapping CH$_2$ vibrational motions. By changing the pump-probe delay range used for the Fourier transform, we identify when specific frequency components contribute during the excited-state dynamics. Methyl substitution reduces the C=C stretching and CCC bending frequencies and introduces an additional frequency component in 1,2-butadiene during the first 90 fs. We further show the importance of sub-20-fs, and ultimately few-femtosecond, temporal resolution for retrieving these frequency components. Frequency-resolved UED therefore provides the vibrational frequencies, internuclear distances, and reaction times associated with photoinduced structural dynamics.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2608.30868",
  "author_total": 4,
  "authors": [
    {
      "name": "Rosalie Tabarie"
    },
    {
      "name": "Simon P. Neville"
    },
    {
      "name": "Michael Schuurman"
    },
    {
      "name": "Kasra Amini"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/81cn5nb41k407.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2608.30868",
  "fulltext_url": null,
  "id": "81cn5nb41k407",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2608.30868",
  "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": null,
  "pdf_url": "https://arxiv.org/pdf/2608.30868",
  "pmcid": null,
  "pmid": null,
  "published": "2026-08-31",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/81cn5nb41k407.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:41Z",
      "native_id": "2608.30868",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2608.30868"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "arxiv:physics.chem-ph",
      "subfield": "physical"
    }
  ],
  "title": "Frequency-resolved ultrafast electron diffraction: visualizing vibrational dynamics in frequency- and real-space",
  "title_text": "Frequency-resolved ultrafast electron diffraction: visualizing vibrational dynamics in frequency- and real-space",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:41Z",
  "url": "https://research.draconitic.com/paper/81cn5nb41k407",
  "venue": "arXiv",
  "versions": []
}