| Project/Area Number |
20K15229
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 32010:Fundamental physical chemistry-related
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Project Period (FY) |
2020-04-01 – 2024-03-31
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| Project Status |
Completed (Fiscal Year 2023)
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| Budget Amount *help |
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2022: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2021: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2020: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
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| Keywords | electron spectroscopy / electron scattering / liquid water / photoelectron anisotropy / aqueous solution / synchrotron radiation |
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| Outline of Research at the Start |
Important for many chemical and biological processes is a solute’s propensity vs. depth and its orientation at the surface, which is measured with photoelectron spectroscopy by exploiting electron scattering. We quantify how electrons scatter and loose energy in aqueous solutions for this purpose.
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| Outline of Annual Research Achievements |
The project is about electron scattering mechanisms in liquid water and aqueous solutions and its impact on photoelectron angular distributions using photoelectron spectroscopy in international collaboration. Electron scattering is crucial for understanding energy deposition, radical formation, and biological damage by slow and fast electrons, and for interpreting of spectra from aqueous solutions.
The last year had several applications of the newly found understanding of electron scattering. Various surface-active solutes were studied, ranging from atmospherically-relevant organic molecular ions to prototypical species, which change their surface propensity as a function of pH value (i.e., the protonation state of the molecule). The former showed than the presence of multiple surface-active species can have a cooperative effect, strongly enhancing their surface propensity. This has large implications for the availability of species in atmospheric reactions. For the latter, we could show that the photoelectron signal and angular distribution are sensitively dependent on the surface propensity, which can be used as a precise depth scale into the solution. These studies are prepared for publication.
A newly developed method enabled us to study the work function (surface potential) and changes of the electronic structure of an aqueous solution as a function of solute concentration for the first time. This lays the foundation for extracting electrochemically relevant parameters, such as the electrochemical potential from aqueous solution, directly via photoelectron spectroscopy.
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