Hiroki Kobayashi

Current Position

PhD Student

Geochemical Research Centre, Graduate School of Science, The University of Tokyo. Supervised by Kazuki Komatsu and Hiroyuki Kagi.

Research Interests

Education & Positions

Publications (Corresponding Author)

1. Hiroki Kobayashi*, Kazuki Komatsu, Shinichi Machida, Takanori Hattori, Hiroyuki Kagi. Ice IV from Supercooled Water: Reproducible Crystallization, Structure, and Ordering. The Journal of Physical Chemistry C (2026). DOI:10.1021/acs.jpcc.6c00737
2. Hiroki Kobayashi*, Kazuki Komatsu, Hiroyuki Kagi. Densification processes of crystalline purine: Negative linear compressibility and pressure-induced phase transition. Chemical Physics Letters 884, 142600 (2025). DOI:10.1016/j.cplett.2025.142600
3. Hiroki Kobayashi*, Kazuki Komatsu, Hayate Ito, Shinichi Machida, Takanori Hattori, Hiroyuki Kagi. Slightly Hydrogen-Ordered State of Ice IV Evidenced by In-Situ Neutron Diffraction. The Journal of Physical Chemistry Letters 14, 10664 (2023). DOI:10.1021/acs.jpclett.3c02563

Awards

1. Aug. 2025.IUCr Young Scientist Award (for attendance at ECM35)
2. Feb. 2025.Ludo Frevel Crystallography Scholarship Award from 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 attendance at IUCr2023)
5. Mar. 2022.Department of Chemistry Chair Award (for BSc studies), Faculty of Science, UTokyo

Grants

1. 04/2026 – 03/2028.JSPS Research Fellowships for Young Scientists (DC2). "Structural diversity of salty ice: generalised understanding focusing on density, crystal structure, and ionic species"
2. 02/2025 – 02/2026.JSPS Overseas Challenge Program for Young Researchers (1,400,000 JPY + travel). "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, The Japan Science Society (880,000 JPY)

I've served as a peer reviewer for:

App & Website Development

• PACE5000.py
  Python-based GUI application for controlling and logging Druck PACE5000
  GitHub
• FluoraPressée
  Python-based GUI application for controlling spectrometer, data acquisition, and real-time pressure calculation (only for Andor spectrometers at the moment)
  GitHub

I've done experiments at:

• KEK-PF
• J-PARC
• SPring-8
• SOLEIL
• ILL
• ISIS

Awarded Beamtimes

1. J-PARC MLF 2026A0300. 5.0 days at BL11 PLANET
2. J-PARC MLF 2024B0255. 8.0 days at BL11 PLANET — Disorder-to-order, order-to-disorder, and order-to-order transitions in ice
3. SPring-8 2024B1732. 18 shifts at BL32XU — 微小液滴からのみ結晶化する未知氷高圧相の結晶構造決定
4. J-PARC MLF 2024A0037. 8.0 days at BL18 SENJU — Conclusive crystal-structure analysis of ice XIX
5. J-PARC MLF 2024A0061. 11.0 days at BL11 PLANET — Crystallography of the ice VI families
6. J-PARC MLF 2023A0195. 8.0 days at BL11 PLANET — Crystal structure and hydrogen-ordering behaviour of ice IV
7. J-PARC MLF 2023A0188. 5.0 days at BL18 SENJU — Crystal-structure analysis of ice XIX by single-crystal neutron diffraction
8. J-PARC MLF 2022B0093. 7.5 days at BL11 PLANET — Exploration into a hydrogen-ordered counterpart of ice IV