| 研究課題/領域番号 |
19K15397
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| 研究種目 |
若手研究
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| 配分区分 | 基金 |
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| 審査区分 |
小区分28030:ナノ材料科学関連
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| 研究機関 | 東京大学 |
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研究代表者 |
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| 研究期間 (年度) |
2019-04-01 – 2024-03-31
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| 研究課題ステータス |
完了 (2023年度)
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| 配分額 *注記 |
4,160千円 (直接経費: 3,200千円、間接経費: 960千円)
2022年度: 780千円 (直接経費: 600千円、間接経費: 180千円)
2021年度: 780千円 (直接経費: 600千円、間接経費: 180千円)
2020年度: 1,300千円 (直接経費: 1,000千円、間接経費: 300千円)
2019年度: 1,300千円 (直接経費: 1,000千円、間接経費: 300千円)
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| キーワード | metal surface / hydrogen / electronic friction / charge exchange / energy dissipation / anisotropic / nanostructure / nanojunction / ortho-para / DFT / NEGF / molecule / graphene / quantum effects / hydrogen storage / nuclear spin / 2D nanostructure / transition metal / Quantum effects / nanostructures / ortho-para conversion / molecular rotations |
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| 研究開始時の研究の概要 |
The current trend in high-capacity hydrogen storage research is the usage of nanomaterials due to their large surface areas and amenability to engineering. Due to its light mass, quantum effects are likely to play essential roles in hydrogen binding and dynamics in nanostructures. In this research, the quantum mechanical effects in hydrogen storage will be explored by means of first principles calculations and time-dependent perturbation theory. The results of this research are expected to introduce new paradigms in research approaches to hydrogen storage and hydrogen related technologies.
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| 研究実績の概要 |
This year, the hydrogen molecule's (H2) rotational state in a nanojunction has been investigated by means of model Hamiltonian calculations. We extended the formulations to account for both the effects of the environment which was represented by a phonon bath and the molecular vibration. The walls of the nanojunction were modeled by an infinite metal surface and the interaction with H2 has been considered using a phenomenological Hamiltonian. Using this simplified model, we derived the orientation-dependent charge exchange and the electronic friction coefficient of the scattering H2. Both charge exchange and electronic friction were found to be highly anisotropic and dependent on the coupling with the environment. We found that the occupation probability after scattering is higher for perpendicular than parallel oriented H2. From the friction coefficient we obtained the average energy dissipated into the excitation of electron-hole in the metal and eventually the sticking probability. Within our chosen parameters, we found that the magnitude of the friction coefficient of H2 oriented perpendicular to the surface is larger than the one oriented parallel. This entails that the former has the larger probability of being adsorbed. Our results have important implications not just in hydrogen storage but also in other fields such as electrocatalysis.
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