Electronic structure characterization of non-aqueous solvents

• Project/Area Number: 18K14178
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 32010:Fundamental physical chemistry-related
• Research Institution: Kyoto University
• Principal Investigator: Thuermer Stephan 京都大学, 理学研究科, 准教授 (40722161)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2019: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000); Fiscal Year 2018: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
• Keywords: electron spectroscopy / electronic structure / ionization energy / non-aqueous solvents / valence band

Outline of Final Research Achievements

Photoelectron spectroscopy was used to study the electronic structure of liquids, with focus on non-aqueous solvents. Photoelectron spectroscopy is able to directly reveal electrochemical properties, the chemical state and reaction products on a molecular scale, which is also crucial for understanding biological processes. However, the key is having robust reference data and the ability to measure accurate ionization energies.
A new energy-referencing method for obtaining accurate ionization energies was developed and applied to liquid water and alcohols. Here, the full valence band of ethanol and methanol was characterized for the first time. Furthermore, measurements of liquid ammonia have been made possible in international collaboration, which enabled first direct study of an insulator-to-metal transition in an alkali metal-ammonia solution. The gained knowledge was applied to study metallic water-solutions by forming a liquid water layer on a sodium-potassium droplet.

Academic Significance and Societal Importance of the Research Achievements

Important steps for photoelectron spectroscopy on liquids were achieved: Development of a new energy-referencing method for obtaining more accurate chemical properties, and establishing much-needed reference data for non-aqueous solvents, starting with the characterization of methanol and ethanol.

Research Products

• [Int'l Joint Research] Fritz Haber Institute/Helmholtz Zentrum Berlin/DESY Hamburg(ドイツ)
• [Int'l Joint Research] Czech Academy of Sciences(チェコ)
• [Int'l Joint Research] Fritz Haber Institute/Helmholtz Zentrum Berlin/Humboldt-Universitaet zu Berlin(ドイツ)
• [Int'l Joint Research] Czech Academy of Sciences(チェコ)
• [Journal Article] Valence Photoelectron Spectra of Liquid Methanol and Ethanol Measured Using He II Radiation (2021)
  • Author(s): Thuermer Stephan、Shinno Takatoshi、Suzuki Toshinori
  • Journal Title: The Journal of Physical Chemistry A Volume: 125 Issue: 12 Pages: 2492-2503
  • DOI: 10.1021/acs.jpca.1c00288
  • Peer Reviewed
• [Journal Article] Low-energy constraints on photoelectron spectra measured from liquid water and aqueous solutions (2021)
  • Author(s): Malerz Sebastian、Trinter Florian、Hergenhahn Uwe、Ghrist Aaron、Ali Hebatallah、Nicolas Christophe、Saak Clara-Magdalena、Richter Clemens、Hartweg Sebastian、Nahon Laurent、Lee Chin、Goy Claudia、Neumark Daniel M.、Meijer Gerard、Wilkinson Iain、Winter Bernd、Thuermer Stephan
  • Journal Title: Physical Chemistry Chemical Physics Volume: 23 Issue: 14 Pages: 8246-8260
  • DOI: 10.1039/d1cp00430a
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Photoelectron spectra of alkali metal-ammonia microjets: From blue electrolyte to bronze metal (2020)
  • Author(s): Tillmann Buttersack, Philip E. Mason, Ryan S. McMullen, H. Christian Schewe, Tomas Martinek, Krystof Brezina, Martin Crhan, Axel Gomez, Dennis Hein, Garlef Wartner, Robert Seidel, Hebatallah Ali, Stephan Thuermer, Ondrej Marsalek, Bernd Winter, Stephen E. Bradforth, Pavel Jungwirth
  • Journal Title: Science Volume: 368 Issue: 6495 Pages: 1086-1091
  • DOI: 10.1126/science.aaz7607
  • Peer Reviewed / Int'l Joint Research
• [Presentation] 液体の水、メタノール、エタノールのHe(II)光電子分光 (2019)
  • Author(s): 秦隆敏, Stephan Thuermer, 鈴木俊法
  • Organizer: 分子科学討論会2019
• [Presentation] Exploring non-radiative relaxation processes in X-ray irradiated liquid water and aqueous solutions (2018)
  • Author(s): Stephan Thuermer
  • Organizer: International Workshop on Trends in Advanced Spectroscopy in Materials Science (TASPEC)
• [Presentation] Post-collision interaction in liquid water and aqueous solution - A sensitive probe of dynamic screening effects within the Auger-time window? (2018)
  • Author(s): Stephan Thuermer
  • Organizer: The Fourteenth International Conference on Electronic Spectroscopy and Structure (ICESS-14)
  • Int'l Joint Research
• [Remarks] Google Scholar User Profile
  • URL: https://scholar.google.com/citations?user=05yx0h0AAAAJ
• [Remarks] University Group Homepage
  • URL: http://kuchem.kyoto-u.ac.jp/bukka/
• [Remarks] Personal Google Scholar Page
  • URL: https://scholar.google.co.jp/citations?user=05yx0h0AAAAJ