※ 半角英数字
 年 ~ 
検索結果: 13 件中 1件目~13件目を表示
  • 1


Initialising ...



Initialising ...


Initialising ...


Initialising ...


Initialising ...


Initialising ...


Initialising ...


Initialising ...



Rotational-energy transfer in H$$_{2}$$ ortho-para conversion on a metal surface; Interplay between electron and phonon systems

植田 寛和; 福谷 克之

Journal of Physical Chemistry Letters (Internet), 14(34), p.7591 - 7596, 2023/08

Clarifying energy transfer processes in molecular adsorption on solid surfaces is essential to understand gas-surface interaction. Unlike the vibrational-energy transfer processes, which are thought to be well understood in detail, the rotational-energy transfer process still remains unclear. Considering the interconversion between ortho and para states of H$$_{2}$$ is accompanied by the nuclear spin flip and the rotational-energy transfer, the surface-temperature dependence of the ortho-to-para conversion of molecularly chemisorbed H$$_{2}$$ on Pd(210) is studied. The conversion rate is accelerated with increasing surface temperature. Based on the conversion model proposed for metal surfaces, we analyze the temperature dependence of the conversion rate taking account of both electron and phonon systems of the substrate. The rotational-energy transfer is most likely mediated by surface electrons with an assistance of the substrate phonons.


Selective epitaxial growth of Ca$$_{2}$$NH and CaNH thin films by reactive magnetron sputtering under hydrogen partial pressure control

Chon, S.*; 福谷 克之; 他8名*

Journal of Physical Chemistry Letters (Internet), 13(43), p.10169 - 10174, 2022/11

Calcium compounds with N and H are promising catalysts for NH$$_{3}$$ conversion, and their epitaxial thin films provide a platform to quantitatively understand the catalytic activities. Here we report the selective epitaxial growth of Ca$$_{2}$$NH and CaNH thin films by controlling the hydrogen partial pressure ($$P_{H_{2}}$$) during reactive magnetron sputtering. We find that the hydrogen charge states can be tuned by $$P_{H_{2}}$$: Ca$$_{2}$$NH containing H$$^{-}$$ is formed at $$P_{H_{2}}<0.04$$ Pa, while CaNH containing H$$^{+}$$ is formed at $$P_{H_{2}}>0.04$$ Pa. In situ plasma emission spectroscopy reveals that the intensity of the Ca atomic emission ($$sim$$422 nm) decreases as $$P_{H_{2}}$$ increases, suggesting that Ca reacts with H$$_{2}$$ and N$$_{2}$$ to form Ca$$_{2}$$NH at lower $$P_{H_{2}}$$, whereas at higher $$P_{H_{2}}$$, CaH$$_{x}$$ is first formed on the target surface and then sputtered to produce CaNH. This study provides a novel route to control the hydrogen charge states in Ca-N-H epitaxial thin films.


Development of heavy element chemistry at interfaces; Observing actinide complexes at the oil/water interface in solvent extraction by nonlinear vibrational spectroscopy

日下 良二; 渡邉 雅之

Journal of Physical Chemistry Letters (Internet), 13(30), p.7065 - 7071, 2022/08

 被引用回数:2 パーセンタイル:61.67(Chemistry, Physical)

Understanding the chemistry of elements at the bottom of the periodic table is a challenging goal in chemistry. Observing actinide species at interfaces using interface-selective second-order nonlinear optical spectroscopy, such as vibrational sum frequency generation (VSFG) spectroscopy, is a promising route for developing heavy element chemistry; however, such attempts are scarce. Here, we investigated the phase transfer mechanism of uranyl ions (UO$$_{2}$$$$^{2+}$$) in solvent extraction using the di-(2-ethylhexyl)phosphoric acid (HDEHP) extractant dissolved in dodecane organic phase by probing the oil/water liquid-liquid interface using VSFG spectroscopy. The POO$$^{-}$$ symmetric stretch vibrational signals of the HDEHP ligands clearly demonstrated that uranyl ions form interfacial complexes with HDEHP at the oil/water interface. The interfacial uranyl-HDEHP complexes were formed with uranyl ions coming from both the aqueous and oil phases, strongly suggesting that the interfacial complex is an intermediate to cross the oil/water interface. Density functional theory (DFT) calculations proposed the molecular structure of the interfacial uranyl-HDEHP complex.


Crystalline fully carboxylated polyacetylene obtained under high pressure as a Li-ion battery anode material

Wang, X.*; Tang, X.*; Zhang, P.*; Wang, Y.*; Gao, D.*; Liu, J.*; Hui, K.*; Wang, Y.*; Dong, X.*; 服部 高典; et al.

Journal of Physical Chemistry Letters (Internet), 12(50), p.12055 - 12061, 2021/12

 被引用回数:5 パーセンタイル:51.03(Chemistry, Physical)



Freezable and unfreezable hydration water; Distinct contributions to protein dynamics revealed by neutron scattering

山本 直樹*; 古府 麻衣子; 中島 健次; 中川 洋; 柴山 修哉*

Journal of Physical Chemistry Letters (Internet), 12(8), p.2172 - 2176, 2021/03

 被引用回数:8 パーセンタイル:74.41(Chemistry, Physical)



Neutron spin-echo studies of the structural relaxation of network liquid ZnCl$$_2$$ at the structure factor primary peak and prepeak

Luo, P.*; Zhai, Y.*; Leao, J. B.*; 古府 麻衣子; 中島 健次; Faraone, A.*; Zhang, Y.*

Journal of Physical Chemistry Letters (Internet), 12(1), p.392 - 398, 2021/01

 被引用回数:3 パーセンタイル:31.91(Chemistry, Physical)

典型的なネットワークイオン性液体ZnCl$$_2$$の第1およびプレ回折ピークでの微視的な構造緩和を中性子スピンエコー分光により調べた。第1構造ピークの緩和はプレピークのものより速く、活性化エネルギーは約33%高い。融点より十分高温においても、伸長指数関数で記述される緩和が観測された。驚くべきことに、とくに第1ピークにおいて、非指数関数性パラメータは冷却とともに急激に増加し、$$T_{rm m}$$に向かって緩和は伸長指数型から指数型へと変わる。これらの結果は、過冷却状態の典型的なガラス的ダイナミクスが平衡液体で現れること、2つの異なる空間スケールの運動の活性化エネルギーが冷却に伴うネットワーク構造の形成と関連していることを示唆する。


Gas barrier properties of chemical vapor-deposited graphene to oxygen imparted with sub-electronvolt kinetic energy

小川 修一*; 山口 尚登*; Holby, E. F.*; 山田 貴壽*; 吉越 章隆; 高桑 雄二*

Journal of Physical Chemistry Letters (Internet), 11(21), p.9159 - 9164, 2020/11

 被引用回数:3 パーセンタイル:20.45(Chemistry, Physical)



Nanoscale relaxation in "Water-in-Salt" and "Water-in-Bisalt" electrolytes

Gonzal$'e$z, M. A.*; Borodin, O.*; 古府 麻衣子; 柴田 薫; 山田 武*; 山室 修*; Xu, K.*; Price, D. L.*; Saboungi, M.-L.*

Journal of Physical Chemistry Letters (Internet), 11(17), p.7279 - 7284, 2020/09

 被引用回数:13 パーセンタイル:75.98(Chemistry, Physical)

"Water-in-salt" (WIS) and "water-in-bisalt" (WIBS) electrolytes have recently been developed for Li-ion batteries. We report Quasielastic Neutron Scattering (QENS) measurements on solutions of a WIS electrolyte at two concentrations, and a WIBS electrolyte at one concentration. The data were Fourier transformed to obtain experimental intermediate scattering functions (ISFs) and compared with corresponding quantities obtained from Molecular Dynamics (MD) simulations. Both QENS and MD ISFs could be fitted well by a single stretched exponential function to obtain apparent translational diffusion coefficients for the water molecules. The QENS values agree well with the MD simulations for the solutions of a WIS electrolyte at two concentrations, but MD simulations predict a slower relaxation of water compared to QENS for the WIBS electrolyte. Comparison of the incoherent and coherent scattering reveals much faster water dynamics compared with structural relaxation of the ionic framework.


Surface coverage dependence of spin-to-charge current across Pt/MoS$$_{2}$$/Y$$_{3}$$Fe$$_{5}$$O$$_{12}$$ layers via longitudinal spin Seebeck effect

Lee, W.-Y.*; Park, N.-W.*; Kang, M.-S.*; Kim, G.-S.*; Jang, H. W.*; 齊藤 英治; Lee, S.-K.*

Journal of Physical Chemistry Letters (Internet), 11(13), p.5338 - 5344, 2020/07

 被引用回数:10 パーセンタイル:63.79(Chemistry, Physical)

The voltage induced by the inverse spin Hall effect (ISHE) is affected by several factors, including the spin Hall angle of the normal metal (NM), the quality and magnetic properties of the ferromagnetic material (FM), and the interface conditions between the NM and FM bilayers in longitudinal spin Seebeck effect (LSSE) measurement. Specifically, the interface conditions in NM/FM systems via LSSE devices play a crucial role in determining the efficiency of spin current injection into the NM layer. In this letter, we report a new approach to controlling the efficiency of spin current injection into a Pt layer across a Pt/Y$$_{3}$$Fe$$_{5}$$O$$_{12}$$ (YIG) interface by surface coverage of the intermediate layer. A continuous, large-area multilayer molybdenum dichalcogenide (MoS$$_{2}$$) thin film grown by chemical vapor deposition is inserted between the Pt and YIG layers in the LSSE configuration. We found that, when the large-area multilayer MoS$$_{2}$$ film was present, the measured ISHE-induced voltage and theoretically calculated spin current in the Pt/MoS$$_{2}$$/YIG trilayer increased by $$sim$$510% and 470%, respectively, compared to those of a Pt/YIG bilayer. The induced voltage and spin current were very sensitive to the surface conductance, which was affected by the surface coverage of the multilayer MoS$$_{2}$$ films in the LSSE measurement. Furthermore, the theoretically calculated spin current and spin mixing conductance in the trilayer geometry are in qualitatively good agreement with the experimental observations. These measurements enable us to explain the effect of the interface conditions on the spin Seebeck effect in spin transport.


Segmental motions of proteins under non-native states evaluated using quasielastic neutron scattering

藤原 悟*; 松尾 龍人*; 杉本 泰伸*; 柴田 薫

Journal of Physical Chemistry Letters (Internet), 10(23), p.7505 - 7509, 2019/12

 被引用回数:4 パーセンタイル:23.54(Chemistry, Physical)

無秩序なポリペプチド鎖のダイナミクスの特性評価は、本質的に無秩序状態なタンパク質およびフォールディングプロセスに関連する非ネイティブ状態下のタンパク質の挙動を解明するために必要である。本研究では、小角X線散乱測定データと動的光散乱測定データと組み合わせて準弾性中性子散乱測定データから、タンパク質のセグメント運動と分子全体の拡散および局所側鎖運動を評価する方法を独自に開発した。そしてこの方法を、非フォールディング状態およびメルトグロビュール(MG)状態のタンパク質RNase Aに適用し、セグメント運動から生じる拡散係数を評価し、非フォールディング状態とMG状態で異なる値をとることを明らかにした。またこの方法で得られた値は、蛍光現象を用いた別の測定技術を使用して得られた値と一致していることも確認できた。これらの研究成果は、この方法の、さまざまな無秩序状態でのタンパク質の挙動を特徴付ける実行可能性だけでなく、有用性も示している。


Finding free-energy landmarks of chemical reactions

志賀 基之; Tuckerman, M. E.*

Journal of Physical Chemistry Letters (Internet), 9(21), p.6207 - 6214, 2018/11

 被引用回数:4 パーセンタイル:18.84(Chemistry, Physical)



Intrinsic edge asymmetry in narrow zigzag hexagonal heteroatomic nanoribbons causes their subtle uniform curvature

Avramov, P.; Fedorov, D. G.*; Sorokin, P. B.*; 境 誠司; 圓谷 志郎; 大伴 真名歩; 松本 吉弘; 楢本 洋*

Journal of Physical Chemistry Letters (Internet), 3(15), p.2003 - 2008, 2012/08

 被引用回数:34 パーセンタイル:79.2(Chemistry, Physical)

The atomic and electronic structure of narrow zigzag nanoribbons with finite length, consisting of graphene terminated by fluorine on one side, hexagonal ($$h$$)-BN, and $$h$$-SiC were studied with density functional theory. It is found that the asymmetry of nanoribbon edges causes a uniform curvature of the ribbons due to structural stress in the aromatic ring plane. Narrow graphene nanoribbons terminated with fluorine on one side demonstrate a considerable out-of-plane bend, suggesting that the nanoribbon is a fraction of a conical surface. It is shown that the intrinsic curvature of the narrow nanoribbons destroys the periodicity and results in a systematic cancellation of the dipole moment. The in- and out-of-plane curvature of thin arcs allows their closure in nanorings or cone fragments of giant diameter.


First observation of picosecond kinetics of hydrated electrons in supercritical water

室屋 裕佐*; Lin, M.; De Waele, V.*; 籏野 嘉彦; 勝村 庸介; Mostafavi, M.*

Journal of Physical Chemistry Letters (Internet), 1(1), p.331 - 335, 2010/01

 被引用回数:43 パーセンタイル:81.95(Chemistry, Physical)


13 件中 1件目~13件目を表示
  • 1