{
  "abstract": "This work presents the spatially resolved mapping of methane decomposition chemistry in a short direct-current glow discharge, revealing segregated zones for dissociation and polymerization in an Ar-CH4 mixture at 400 mTorr. Laser-induced fluorescence (LIF), two-photon absorption LIF (TALIF), and optical emission spectroscopy (OES), are used to map the absolute number densities of atomic hydrogen (H), methylidyne (CH), and dicarbon (C2) radicals. The results reveal a segregated chemical environment driven by the non-local electron kinetics. The primary dissociation of methane is confined to the cathode sheath (< 4 mm), where the H atom density peaks at a value (). Analysis of the Halpha} line profile identifies two distinct suprathermal H atom populations with peak kinetic energies of ~110 eV and ~17.5 eV, attributed to ion-surface reflection and electron-impact dissociation, respectively. The densities of secondary radicals CH and C2 peak further from the cathode at the sheath-negative glow boundary (y=4-6 mm), identifying this region as the primary zone for polymerization, with the peak C2 density higher than that of CH by a factor of ~370. The discharge operates under strong non-equilibrium conditions, confirmed by the disparity between the low bulk gas temperature (~570 K) and the high vibrational temperature (3300-4700 K) of the emitting CH(A) radicals, the latter serving as a signature of a specific high-energy dissociative excitation pathway. This work demonstrates how the structured energy landscape of a short glow discharge spatially separates methane dissociation from subsequent polymerization. Kinetic estimates suggest that suprathermal H atoms may play a role in bulk plasma chemistry via abstraction reactions, with predicted CH4 activation rates exceeding those of the thermal H population.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Journal reference: Shurik Yatom 2026 Plasma Sources Sci. Technol. 35 085024",
  "arxiv": "2609.17345",
  "author_total": 1,
  "authors": [
    {
      "name": "Shurik Yatom"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/3mczkg7wnc6r7.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.17345",
  "fulltext_url": null,
  "id": "3mczkg7wnc6r7",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.17345",
  "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"
    ],
    [
      "arxiv",
      "physics.plasm-ph"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2609.17345",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-15",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/3mczkg7wnc6r7.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:21:41Z",
      "native_id": "2609.17345",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.17345"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "arxiv:physics.chem-ph",
      "subfield": "physical"
    },
    {
      "field": "physics",
      "origin": "arxiv:physics.plasm-ph",
      "subfield": "plasma"
    }
  ],
  "title": "Spatially-resolved methane decomposition in a short glow discharge: insights into suprathermal hydrogen and radical chemistry",
  "title_text": "Spatially-resolved methane decomposition in a short glow discharge: insights into suprathermal hydrogen and radical chemistry",
  "type": "preprint",
  "updated_at": "2026-10-30T12:21:41Z",
  "url": "https://research.draconitic.com/paper/3mczkg7wnc6r7",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.1088/1361-6595/ae94a9",
      "pid": null,
      "relation": "published-as",
      "title": null,
      "venue": null
    }
  ]
}