Deciphering the third phase structure in uranium extraction with aliphatic amines using combined small-angle X-ray and neutron scattering

Guerinoni, E.*; Zemb, T.*; Motokawa, Ryuhei; Ueda, Yuki; Aoyagi, Noboru; Pellet-Rostaing, S.*; Dourdain, S.*

Journal of Physical Chemistry B, 129(32), p.8210 - 8217, 2025/08

https://doi.org/10.1021/acs.jpcb.5c01917

Solid-state Alder-ene reaction of 1-hexene under high pressure

Xu, J.*; Lang, P.*; Liang, S.*; Zhang, J.*; Fei, Y.*; Wang, Y.*; Gao, D.*; Hattori, Takanori; Abe, Jun*; Dong, X.*; et al.

Journal of Physical Chemistry Letters (Internet), p.2445 - 2451, 2025/00

https://doi.org/10.1021/acs.jpclett.4c03696

The Alder-ene reaction is a chemical reaction between an alkene with an allylic hydrogen, and it provides an efficient method to construct the C-C bond. Traditionally, this reaction requires catalysts, high temperatures, or photocatalysis. In this study, we reported a high-pressure-induced solid-state Alder-ene reaction of 1-hexene at room temperature without a catalyst. 1-Hexene crystallizes at 4.3 GPa and polymerizes at 18 GPa, forming olefins. By exploring gas chromatography-mass spectrometry, we discovered that 1-hexene generates dimeric products through the Alder-ene reaction under high pressures. The in situ neutron diffraction shows that the reaction process did not obey the topochemical rule. A six-membered ring transition state including one C-H bond and two alkene bonds was evidenced by the theoretical calculation, whose energy obviously decreased when compressed to 20 GPa. Our work offers a novel and promising method to realize the Alder-ene reaction at room temperature without a catalyst, expanding the application of this important reaction.

Coverage dependence upon early oxidation stages of hafnium-adsorbed Si(111)-77

Kakiuchi, Takuhiro*; Anai, Ryota*; Saiki, Taiju*; Tsuda, Yasutaka; Yoshigoe, Akitaka

Journal of Physical Chemistry C, 128(31), p.13052 - 13063, 2024/08

https://doi.org/10.1021/acs.jpcc.4c02368

0xidation at the interface and the surface of Si(111) substrate with thin Hf films were studied using synchrotron radiation photoelectron spectroscopy in conjunction with supersonic oxygen molecular beams (SOMB). An Hf/Si(111) with a coverage of 0.5 monolayer (ML) included HfSi and HfSi. Following exposures to thermal oxygen molecules with a translational energy (Et) of 0.03 eV, HfSi was oxidized into Hf valence. Following SOMB irradiation with Et of 0.39 eV, the other HfSi could be oxidized into the Hf. Following the thermal O exposures, the metallic Hf was nonlocally oxidized to HfO via trapping-mediated dissociative adsorption. Meanwhile, the segregated Si atoms were oxidized by SOMB irradiation with 2.2 eV and SiO was generated on the surface.

H molecule generation from dissociatively adsorbed water on TiO through photoexcitation

Kato, Koichi*; Nagatsuka, Naoki*; Fukutani, Katsuyuki

Journal of Physical Chemistry C, 128(20), p.8188 - 8198, 2024/05

https://doi.org/10.1021/acs.jpcc.3c08216

Atomic structure and dynamics of organic-inorganic hybrid perovskite formamidinium lead iodide

Yu, C.*; Kawakita, Yukinobu; Kikuchi, Tatsuya*; Kofu, Maiko*; Honda, Takashi*; Zhang, Z.*; Zhang, Z.*; Liu, Y.*; Liu, S. F.*; Li, B.*

Journal of Physical Chemistry Letters (Internet), 15(1), p.329 - 338, 2024/01

https://doi.org/10.1021/acs.jpclett.3c02498

Water fraction dependence of the aggregation behavior of hydrophobic fluorescent solutes in water-tetrahydrofuran

Tsuji, Hayato*; Nakahata, Masaki*; Hishida, Mafumi*; Seto, Hideki*; Motokawa, Ryuhei; Inoue, Takeru*; Egawa, Yasunobu*

Journal of Physical Chemistry Letters (Internet), 14(49), p.11235 - 11241, 2023/12

https://doi.org/10.1021/acs.jpclett.3c02882

Slightly hydrogen-ordered state of ice IV evidenced by neutron diffraction

Kobayashi, Hiroki*; Komatsu, Kazuki*; Ito, Hayate*; Machida, Shinichi*; Hattori, Takanori; Kagi, Hiroyuki*

Journal of Physical Chemistry Letters (Internet), 14(47), p.10664 - 10669, 2023/11

https://doi.org/10.1021/acs.jpclett.3c02563

Ice IV is a metastable high-pressure phase of ice in which the water molecules exhibit orientational disorder. Although orientational ordering is commonly observed for other ice phases, it has not been reported for ice IV. We conducted powder neutron diffraction experiments for DCl-doped DO ice IV to investigate hydrogen ordering in ice IV. We found abrupt changes in the temperature derivative of unit cell volume, dV/dT, at about 120 K, and revealed their slightly ordered structure at low temperatures based on the Rietveld method. The occupancy of the D1 site deviates from 0.5; it increased when samples were cooled at higher pressures and reached 0.282(5) at 2.38 GPa, 58 K. Our results evidence the presence of a low-symmetry hydrogen-ordered state corresponding to ice IV. It seems, however, difficult to experimentally access the completely ordered phase corresponding to ice IV by slow cooling at high pressure.

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

Ueta, Hirokazu; Fukutani, Katsuyuki

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

https://doi.org/10.1021/acs.jpclett.3c01209

Hierarchical aggregation in a complex fluid; The Role of isomeric interconversion

Massey, D.*; Williams, C. D.*; Mu, J.*; Masters, A. J.*; Motokawa, Ryuhei; Aoyagi, Noboru; Ueda, Yuki; Antonio, M. R.*

Journal of Physical Chemistry B, 127(9), p.2052 - 2065, 2023/03

https://doi.org/10.1021/acs.jpcb.2c07527

Probing strain and doping along a graphene wrinkle using tip-enhanced Raman spectroscopy

Balois-Oguchi, M. V.*; Hayazawa, Norihiko*; Yasuda, Satoshi; Ikeda, Katsuyoshi*; Nguyen, T. Q.*; Escao, M. C.*; Tanaka, Takuo*

Journal of Physical Chemistry C, 127(12), p.5982 - 5990, 2023/03

https://doi.org/10.1021/acs.jpcc.2c08529

Micrometer-sized wrinkles in graphene are known to affect the electronic properties of graphene due to their shape and the strain variations they create. Here, we analyze the strain distribution and doping of a graphene wrinkle having 1.9 nm width using tip-enhanced Raman spectroscopy (TERS) in ambient conditions. We found a strong correlation between the TERS images of the graphene wrinkle and the electronic Raman scattering (eRS) of the Au(111) substrate. Our work demonstrates that the as-fabricated physical and electronic properties of nanometer-sized features, such as wrinkles, can be probed and studied in detail with TERS which is essential for nanodevice characterization.