Hiroki Kobayashi
I am working as...
- Chercheur invité (Invited Researcher) at Institut de minéralogie, de physique des matériaux et de cosmochimie, Sorbonne University, France (Feb 2025–, Physique des systèmes simples en conditions extrêmes (PHYSIX) group, hosted by Dr Stephan Klotz)
- PhD student at Geochemical Research Centre (Kagi/Komatsu Group), Graduate School of Science, the University of Tokyo, Japan
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
, 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
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
Awards
- 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)
- Mar 2024: Graduate School of Science Awards (for Master's studies), UTokyo
- Aug. 2023: CrSJ Travel Award (fund from the Japanese Crystallographic Society for the attendance at IUCr2023)
- Mar. 2022: Department of Chemistry Chair Award (for BSc studies), Faculty of Science, UTokyo
Grants
- 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"
- FY2024. Sasakawa Scientific Research Grant from The Japan Science Society (880,000 JPY)
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.