Tei, C.; Otaka, Masahiko; Kuwahara, Daisuke*
Chemical Physics Letters, 829, p.140755_1 - 140755_6, 2023/10
We were able to detect the nuclear magnetic resonance (NMR) signal of a liquid sodium clinging to the interface of solid metal particles for the first time. In this study, we confirmed the difference in the relaxation times due to the difference in the interactions between liquid sodium and metal particles suspended in the liquid sodium. It was found that the surface of the micro titanium particles and liquid metallic sodium interact physically, not chemically.
Hirato, Misaki*; Yokoya, Akinari*; Baba, Yuji*; Mori, Seiji*; Fujii, Kentaro*; Wada, Shinichi*; Izumi, Yudai*; Haga, Yoshinori
Physical Chemistry Chemical Physics, 25(21), p.14836 - 14847, 2023/05
Nakanishi, Takumi*; Hori, Yuta*; Shigeta, Yasuteru*; Sato, Hiroyasu*; Wu, S.-Q.*; Kiyanagi, Ryoji; Munakata, Koji*; Ohara, Takashi; Sato, Osamu*
Physical Chemistry Chemical Physics, 25(17), p.12394 - 12400, 2023/05
Kai, Takeshi; Toigawa, Tomohiro; Ukai, Masatoshi*; Fujii, Kentaro*; Watanabe, Ritsuko*; Yokoya, Akinari*
Journal of Chemical Physics, 158(16), p.164103_1 - 164103_8, 2023/04
New insight into water radiolysis and photolysis is indispensable in the dramatic progress of sciences and technologies in various research areas. In the radiation field, reactive hydrated electrons are considerably produced along radiation tracks. Although the formation results from a transient dynamic correlation between ejected electrons and water, the individual mechanisms of electron thermalization, delocalization, and polarization are unknown. Using a dynamic Monte Carlo code, we show herein that the ejected electrons are immediately delocalized by molecular excitations in parallel with phonon polarization and gradually thermalized by momentum transfer with an orientation polarization in a simultaneous manner. Our results show that these mechanisms heavily depend on the intermolecular vibration and rotation modes peculiar to water. We expect our approach to be a powerful technique for connecting physical and chemical processes in various solvents.
Tsuda, Yasutaka; Yoshigoe, Akitaka; Ogawa, Shuichi*; Sakamoto, Tetsuya*; Yamamoto, Yoshiki*; Yamamoto, Yukio*; Takakuwa, Yuji*
Journal of Chemical Physics, 157(23), p.234705_1 - 234705_21, 2022/12
Matsuda, Shohei; Nakashima, Nobuaki*; Yokoyama, Keiichi; Taniguchi, Seiji*; Chosrowjan, H.*; Somekawa, Toshihiro*; Yatsuhashi, Tomoyuki*
Chemical Physics Letters, 802, p.139759_1 - 139759_6, 2022/09
no abstracts in English
Yamaguchi, Ko*; Kawaguchi, Daisuke*; Miyata, Noboru*; Miyazaki, Tsukasa*; Aoki, Hiroyuki; Yamamoto, Satoru*; Tanaka, Keiji*
Physical Chemistry Chemical Physics, 24(36), p.21578 - 21582, 2022/09
Hirade, Tetsuya; Michishio, Koji*; Kobayashi, Yoshinori*; Oshima, Nagayasu*
Chemical Physics Letters, 795, p.139507_1 - 139507_4, 2022/05
We obtained the temperature dependence up to 150C of the triplet positronium (-Ps) lifetime in N,N,N-Trimethyl-N-propylammonium bis(trifluoromethanesulfonyl)imide (TMPA-TFSI) by the vertical slow positron beamline installed at AIST. Positrons penetrate into the liquid surface of TMPA-TFSI with the positron energies of 2 keV and 12 keV to investigate at the near-surface and the balk. The surface structure was visible at 150C, 120C above the melting temperature. The -Ps lifetime became shorter at higher temperatures for both positron energies. Similar temperature dependence had appeared just in water as the result of the reaction of -Ps and radiolysis products such as the OH radicals. The temperature dependence observed for TMPA-TFSI suggested that the chemical reaction of -Ps occurred.
Thomsen, B.; Shiga, Motoyuki
Physical Chemistry Chemical Physics, 24(18), p.10851 - 10859, 2022/05
Akazawa, Daisuke; Sasaki, Takehiko*; Nagasaka, Masanari*; Shiga, Motoyuki
Journal of Chemical Physics, 156(4), p.044202_1 - 044202_7, 2022/01
The hydration structure of cellulose is very important for understanding the hydrolysis of cellulose at the molecular level. In this paper, we report a joint experimental and theoretical study on the X-ray absorption spectroscopy (XAS) of aqueous cellobiose, a disaccharide unit of cellulose. In the experimental part, high resolution measurements of the carbon K-edge XAS spectra were performed. It was found that the peak heights in the spectrum change considerably over the temperature range of 25 C to 60 C, which is a reflection of the number of hydrogen bonds between cellobiose and water. We suggest that this spectral change could be useful information for identifying the hydration of cellulose in various environments.
Thomsen, B.; Shiga, Motoyuki
Journal of Chemical Physics, 155(19), p.194107_1 - 194107_11, 2021/11
Nagaya, Yuki*; Nakatsu, Hiroki*; Ogura, Shohei*; Shimazaki, Kota*; Ueta, Hirokazu; Takeyasu, Kotaro*; Fukutani, Katsuyuki
Journal of Chemical Physics, 155(19), p.194201_1 - 194201_6, 2021/11
Baba, Yuji*; Shimoyama, Iwao
Chemical Physics, 550, p.111302_1 - 111302_5, 2021/10
The effect of a core-to-valence resonant photoexcitation in an atom on photoemission from the neighboring atoms has been experimentally investigated. For SiO fine powder mixed with boron nitride matrix, it was found that the intensity of the O photoelectrons was reduced around the Si resonant photoexcitation. On the other hand, the intensity of the B or N photoelectrons from the matrix material did not change regardless of the photon energy. Similar phenomenon was also observed for SiN powder mixed with cellulose as a matrix material. The results demonstrated that photoemission from the nearest-neighbor atoms that are directly bound to silicon is perturbated by the core-to-valence resonant photoexcitation in silicon. Using the phenomenon, it is expected that species of the nearest neighbor atom can be identified by a resonant core-level excitation in a target atom.
Yamaguchi, Akiko; Kobayashi, Keita; Takahashi, Yoshio*; Machida, Masahiko; Okumura, Masahiko
Chemical Physics Letters, 780, p.138945_1 - 138945_5, 2021/10
no abstracts in English
Gao, D.*; Tang, X.*; Wang, X.*; Yang, X.*; Zhang, P.*; Che, G.*; Han, J.*; Hattori, Takanori; Wang, Y.*; Dong, X.*; et al.
Physical Chemistry Chemical Physics, 23(35), p.19503 - 19510, 2021/09
Pressure-induced phase transition and polymerization of nitrogen-rich molecules are widely focused due to its extreme importance for the development of green high energy density materials. Here, we present a study of the phase transition and chemical reaction of 1H-tetrazole up to 100 GPa by using Raman, IR, X-ray diffraction, neutron diffraction techniques and theoretical calculation. A phase transition above 2.6 GPa was identified and the high-pressure structure was determined with one molecule in a unit cell. The 1H-tetrazole polymerizes reversibly below 100 GPa, probably through a carbon-nitrogen bonding instead of nitrogen-nitrogen bonding. Our studies updated the structure model of the high pressure phase of 1H-tetrazole, and presented the possible intermolecular bonding route for the first time, which gives new insights to understand the phase transition and chemical reaction of nitrogen-rich compounds, and benefit for designing new high energy density materials.
Kobayashi, Keita; Nagai, Yuki; Itakura, Mitsuhiro; Shiga, Motoyuki
Journal of Chemical Physics, 155(3), p.034106_1 - 034106_9, 2021/07
no abstracts in English
Zhai, Y.*; Luo, P.*; Nagao, Michihiro*; Nakajima, Kenji; Kikuchi, Tatsuya*; Kawakita, Yukinobu; Kienzle, P. A.*; Z, Y.*; Faraone, A.*
Physical Chemistry Chemical Physics, 23(12), p.7220 - 7232, 2021/03
Thomsen, B.; Shiga, Motoyuki
Journal of Chemical Physics, 154(8), p.084117_1 - 084117_10, 2021/02
In this study we investigate the nuclear quantum effects on the acidity constant of liquid water isotopologues at the ambient condition by path integral molecular dynamics simulations. This technique not only reproduces the acidity constants of liquid DO experimentally measured but also allows for a theoretical prediction of the acidity constants of liquid TO, aqueous HDO and HTO, which are unknown due to its scarcity. The results indicate that the nuclear quantum effects play an indispensable role in the absolute determination of acidity constants.
Toigawa, Tomohiro; Peterman, D. R.*; Meeker, D. S.*; Grimes, T. S.*; Zalupski, P. R.*; Mezyk, S. P.*; Cook, A. R.*; Yamashita, Shinichi*; Kumagai, Yuta; Matsumura, Tatsuro; et al.
Physical Chemistry Chemical Physics, 23(2), p.1343 - 1351, 2021/01
The candidate An(III)/Ln(III) separation ligand hexa--octylnitrilo-triacetamide (HONTA) was irradiated under envisioned SELECT (Solvent Extraction from Liquid waste using Extractants of CHON-type for Transmutation) process conditions using a solvent test loop in conjunction with cobalt-60 gamma irradiation. We demonstrate that HONTA undergoes exponential decay with increasing gamma dose to produce a range of degradation products which have been identified and quantified by HPLC-ESI-MS/MS techniques. The combination of HONTA destruction and degradation product ingrowth, particularly dioctylamine, negatively impacts the extraction and back-extraction of both americium and europium ions. The loss of HONTA was attributed to its reaction with the solvent (-dodecane) radical cation of (HONTA + R) = (7.61 0.82) 10 M s obtained by pulse radiolysis techniques. However, when this ligand is bound to either americium or europium ions, the observed -dodecane radical cation kinetics increase by over an order of magnitude. This large reactivity increase to additional reaction pathways occurring upon metal-ion binding. Lastly nanosecond time-resolved measurements showed that both direct and indirect HONTA radiolysis yielded the short-lived (100 ns) HONTA radical cation as well as a longer-lived (s) HONTA triplet excited state. These HONTA species are important precursors to the suite of HONTA degradation products observed.
Higuchi, Yuki*; Setoyama, Daigo*; Isegawa, Kazuhisa; Tsuchikawa, Yusuke; Matsumoto, Yoshihiro*; Parker, J. D.*; Shinohara, Takenao; Nagai, Yasutaka*
Physical Chemistry Chemical Physics, 23(2), p.1062 - 1071, 2021/01
This study is the first report on liquid water and ice imaging conducted at a pulsed spallation neutron source facility. Neutron imaging can be utilised to visualise the water distribution inside polymer electrolyte fuel cells (PEFCs). Particularly, energy-resolved neutron imaging is a methodology capable of distinguishing between liquid water and ice, and is effective for investigating ice formation in PEFCs operating in a subfreezing environment. The distinction principle is based on the fact that the cross sections of liquid water and ice differ from each other at low neutron energies. In order to quantitatively observe transient freezing and thawing phenomena in a multiphase mixture (gas/liquid/solid) within real PEFCs with high spatial resolution, a pulsed neutron beam with both high intensity and wide energy range is most appropriate. In the validation study of the present work, we used water sealed in narrow capillary tubes to simulate the flow channels of a PEFC, and a pulsed neutron beam was applied to distinguish ice, liquid water and super-cooled water, and to clarify freezing and thawing phenomena of the water within the capillary tubes. Moreover, we have enabled the observation of liquid water/ice distributions in a large field of view (300 mm 300 mm) by manufacturing a sub-zero environment chamber that can be cooled down to -30C, as a step towards visualisation of full-size fuel cells.