{
  "abstract": "This study aimed to elucidate the structural evolution of supercritical fluid hydrogen (SCF H2) under high pressure. X-ray diffraction was performed on SCF H2 using synchrotron radiation at room temperature. The structure factor S(Q) was observed in a low-Q region at each pressure, revealing a crossover at around 0.56 GPa, consistent with our previous Raman spectroscopy results. The average volume per molecule was calculated at each pressure using the center-to-center distance between the nearest neighboring H2 molecules, reflecting van der Waals interactions and compression of the internuclear distance. The volumes calculated from the face-centered cubic model were consistent with those derived from the cited equation of state, with a slight discrepancy that increased gradually with the pressure. This finding indicates that further densification following the crossover occurs primarily by intra-atomic/molecular mechanisms rather than intermolecular shortening of distances, which cannot be adequately explained by the close-packed coordination model alone.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Mathematical Science and Physics, Faculty of Science and Engineering, Iwate University, 4-3-5 Ueda, Morioka, Iwate020-8551, Japan.",
    "Graduate School of Arts and Science, Iwate University, 4-3-5 Ueda, Morioka, Iwate020-8551, Japan.",
    "KYOKUGEN, Center for Science and Technology under Extreme Conditions, The University of Osaka, Machikaneyama 1-3, Toyonaka, Osaka560-8531, Japan.",
    "Geodynamics Research Center, Ehime University, 2-5 Bunkyo-Cho, Matsuyama, Ehime790-8577, Japan.",
    "National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba, Ibaraki305-0044, Japan.",
    "Diffraction and Scattering Division, Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo679-5198, Japan.",
    "Office of Institutional Advancement and Communications, Kyoto University, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo679-5198, Japan.",
    "Graduate School of Material Science, University of Hyogo, 3-2-1 Kamigohri, Hyogo678-1297, Japan.",
    "Faculty of Science, Niigata University, 8050 Ikarashi 2-no-cho, Nishi-ku, Niigata950-2181, Japan."
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 10,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Atsuko Nakayama",
      "orcid": "0009-0002-0016-3750"
    },
    {
      "affs": [
        1
      ],
      "name": "Naoto Fujii"
    },
    {
      "affs": [
        1
      ],
      "name": "Koji Hirama"
    },
    {
      "affs": [
        1
      ],
      "name": "Kentaro Hamada"
    },
    {
      "affs": [
        2,
        3
      ],
      "name": "Katsuya Shimizu",
      "orcid": "0000-0003-0560-8325"
    },
    {
      "affs": [
        2
      ],
      "name": "Yuki Nakamoto"
    },
    {
      "affs": [
        4
      ],
      "name": "Satoshi Nakano",
      "orcid": "0000-0002-7010-9867"
    },
    {
      "affs": [
        5,
        6
      ],
      "name": "Saori Kawaguchi-Imada"
    },
    {
      "affs": [
        7
      ],
      "name": "Yuichi Akahama",
      "orcid": "0000-0003-2736-9855"
    },
    {
      "affs": [
        8
      ],
      "name": "Ayako Ohmura"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/fhxyvpdjs4tnn.bib",
  "cited_by": 0,
  "doi": "10.1021/acs.jpclett.6c02439",
  "fulltext_url": "https://europepmc.org/articles/PMC13679091",
  "id": "fhxyvpdjs4tnn",
  "issns": [
    "1948-7185"
  ],
  "landing_url": "https://europepmc.org/article/MED/42918214",
  "language": "eng",
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "1908|High-pressure geophysics and materials"
    ]
  ],
  "openalex": "W7214703763",
  "pdf_url": "https://europepmc.org/articles/PMC13679091?pdf=render",
  "pmcid": "PMC13679091",
  "pmid": "42918214",
  "published": "2026-10-01",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/fhxyvpdjs4tnn.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:20:36Z",
      "native_id": "MED:42918214",
      "source": "europepmc",
      "url": "https://europepmc.org/article/MED/42918214"
    }
  ],
  "subjects": [
    {
      "field": "earth",
      "origin": "openalex:1908|High-pressure geophysics and materials",
      "subfield": "geophysics"
    }
  ],
  "title": "A High-Density Supercritical Fluid of H2.",
  "title_text": "A High-Density Supercritical Fluid of H2.",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:20:36Z",
  "url": "https://research.draconitic.com/paper/fhxyvpdjs4tnn",
  "venue": "The journal of physical chemistry letters",
  "versions": []
}