Hiroki
KOBAYASHI

Hiroki Kobayashi

Hiroki Kobayashi

I am working as...

Research Interest

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

Research Experience

Neutron diffraction, x-ray diffraction, Raman spectroscopy, differential scanning calorimetry

Software Skills: Click here to Show

Languages

English (upper intermediate) & Japanese (native)

Find me at...

✉️: hiroki@eqchem.s.u-tokyo.ac.jp

🔗: ResearchGate, Google Scholar

🇫🇷: BP 115, 4 Place Jussieu, 75252 Paris, France (My office: Room 13-23.330, Amphi 23)

🇯🇵: Room 2702, 7th floor, Chemistry West Building, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.

Research History

  • Feb. 2025 – current. Chercheur invité (Invited Researcher) at Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Sorbonne Université, Paris, France
    Host Researcher: Dr. Stephan Klotz
  • Oct. 2022 - current. World-leading Innovative Graduate Study program for Materials Research, Information, and Technology (MERIT-WINGS), the University of Tokyo.
  • Geochemical Research Center, Graduate School of Science, The University of Tokyo. BSc (Mar. 2022), MSc (Mar. 2024), PhD course (Apr. 2022 – current)
    Thesis supervisor: Prof. Hiroyuki Kagi and Kazuki Komatsu.
  • I've been studying the hydrogen ordering behaviour of high-pressure ice phases. My first research topic was H-ordering of ice IV, which has been published: HK et al., JPCL (2023). In 2022, I also started to study the phase transition of ice VI families (namely VI, XV, and XIX) using calorimetric and crystallographic methods.
  • Throughout the ice-IV project, where I performed lots of crystallisation experiments of amorphous ice, I got interested in how, when, and where such metastable ice phases form – this is one of my current projects.

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
https://doi.org/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.

Forthcoming events

  • I am staying at IMPMC, Sorbonne Univ., Paris, from Feb. 2025 as an invited researcher hosted by Dr Stefan Klotz.
  • Experiments at ILL in May & June
  • Experiments at ISIS in July
Publication ListPresentation ListDiary

Awards

  1. 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)
  2. Mar 2024: Graduate School of Science Awards (for Master's studies), UTokyo
  3. Aug. 2023: CrSJ Travel Award (fund from the Japanese Crystallographic Society for the attendance at IUCr2023)
  4. Mar. 2022: Department of Chemistry Chair Award (for BSc studies), Faculty of Science, UTokyo

Grants

  1. FY2024. 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"
  2. FY2024. Sasakawa Scientific Research Grant from The Japan Science Society (880,000 JPY)