{
  "abstract": "Non-local thermodynamic equilibrium conditions in the interstellar medium require collisional rate coefficients to model astronomical observations; these are usually determined from theoretical scattering calculations. The aim of this study is to measure experimentally low-temperature pressure-broadening cross-sections for the H$_2$CO-He system in order to validate the theoretical methodology involved in determining new collisional rate coefficients. The experiments employed the chirped-pulse in uniform supersonic flow method, and H$_2$CO is generated in situ by 193 nm excimer laser photolysis of tetrahydrofuran in cold He flows. State-of-the-art calculations are performed by computing a new potential energy surface for the H$_2$CO-He system which is subsequently implemented in scattering calculations using the close-coupling method to derive pressure broadening cross-sections and collisional rate coefficients. Excellent agreement between theory and experiment is obtained, with the calculated values falling within the 95 % confidence intervals of the experimental measurements. Such agreement validates the high accuracy of the theoretical data. Helium constitutes about 20 % relative to H$_2$ in the interstellar medium. The inclusion of collisional rate coefficients for H$_2$CO with He in radiative transfer modelling leads to variations in the excitation temperature of frequently detected rotational lines of up to 12 % in warm regions such as protostars.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2606.07039",
  "author_total": 5,
  "authors": [
    {
      "name": "Chinmai Sai Jureddy"
    },
    {
      "name": "Sandor Demes"
    },
    {
      "name": "Francesca Tonolo"
    },
    {
      "name": "Francois Lique"
    },
    {
      "name": "Ian R. Sims"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/4dp4ntz44db8k.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2606.07039",
  "fulltext_url": null,
  "id": "4dp4ntz44db8k",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2606.07039",
  "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",
      "astro-ph.IM"
    ],
    [
      "arxiv",
      "physics.chem-ph"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2606.07039",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-04",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/4dp4ntz44db8k.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:19:14Z",
      "native_id": "2606.07039",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2606.07039"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.IM",
      "subfield": "instrumentation-methods"
    },
    {
      "field": "chemistry",
      "origin": "arxiv:physics.chem-ph",
      "subfield": "physical"
    }
  ],
  "title": "Collisional excitation of H$_2$CO by He: Experimental validation of state-of-the-art scattering calculations",
  "title_text": "Collisional excitation of H_2CO by He: Experimental validation of state-of-the-art scattering calculations",
  "type": "preprint",
  "updated_at": "2026-10-30T12:19:14Z",
  "url": "https://research.draconitic.com/paper/4dp4ntz44db8k",
  "venue": "arXiv",
  "versions": []
}