Hiroki Kobayashi

Hiroki Kobayashi

I am working as...

Research Interest

High-pressure, water, ice, aqueous solutions, phase transition, crystallography, experimental mineral physics and chemistry

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Languages

English (upper intermediate) & Japanese (native)

Research History

  • Feb. 2025 – current. Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Université. Chercheur invité (Invited Researcher).
  • Apr. 2021 – current. Geochemical Research Center, Graduate School of Science, The University of Tokyo.

Recent news

  • I am staying at IMPMC, Sorbonne Univ., Paris, from Feb. 2025 as an invited researcher hosted by Dr Stefan Klotz.
  • I discovered three new phases of ice and their structure arXiv preprint
  • We reported weak hydrogen ordering in ice IV H.K. et al., JPCL (2023)

Featured Works

Slightly Hydrogen-Ordered State of Ice IV Evidenced by In-Situ Neutron Diffraction

Hiroki Kobayashi*, Kazuki Komatsu, Hayate Ito, Shinichi Machida, Takanori Hattori, and Hiroyuki Kagi.

The Journal of Physical Chemistry Letters (2023) 14 10664
DOI: 10.1021/acs.jpclett.3c02563

We reported crystallographic evidence for the hydrogen ordering in ice IV by neutron diffraction. It shows discontinuous behaviour at 120 K and Rietveld analysis at the low-T side suggests it is a very weak hydrogen ordering structural transition.

Awards

  1. Aug. 2025: IUCr Young Scientist Award (for the attendance at ECM35)
  2. Feb. 2025: Ludo Frevel Crystallography Scholarship Award from International Centre for Diffraction Data (ICDD). "In-depth neutron diffraction study of unusual hydrogen ordering behaviour in ice VI" (2,500 USD)
  3. Mar. 2024: Graduate School of Science Awards (for MSc studies), UTokyo
  4. Aug. 2023: CrSJ Travel Award (for the attendance at IUCr2023)
  5. Mar. 2022: Department of Chemistry Chair Award (for BSc studies), Faculty of Science, UTokyo

Grants

  1. 04/2026 – 03/2028. Research Fellowships for Young Scientists from Japan Society of Promotion of Science (JSPS). "Structural diversity of salty ice: generalised understanding focusing on density, crystal structure, and ionic species"
  2. 02/2025 – 02/2026. Overseas Challenge Program for Young Researchers (1,400,000 JPY + transportation costs) from Japan Society of Promotion of Science (JSPS). "Precise analysis of the hydrogen-atom distribution in a high-pressure phase of ice by single-crystal neutron diffraction"
  3. 04/2024 – 02/2025. Sasakawa Scientific Research Grant from The Japan Science Society (880,000 JPY)