Conformation, hydration, and ligand exchange process of ruthenium nitrosyl complexes in aqueous solution; Free-energy calculations by a combination of molecular-orbital theories and different solvent models

Kido, Kentaro; Kaneko, Masashi

Journal of Computational Chemistry, 44(4), p.546 - 558, 2023/02

AA2022-0469.pdf:1.33MB

https://doi.org/10.1002/jcc.27021

Development of tailor-made adsorbents for uranium recovery from seawater on the basis of uranyl coordination chemistry (Contract research); FY2020 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Tokyo Institute of Technology*

JAEA-Review 2021-041, 42 Pages, 2022/01

JAEA-Review-2021-041.pdf:2.03MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2020. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2019, this report summarizes the research results of the "Development of tailor-made adsorbents for uranium recovery from seawater on the basis of uranyl coordination chemistry" conducted in FY2020. On the basis of deep understanding on uranyl coordination chemistry, we design molecular structures of pentadentate ligands as functional moieties for uranium adsorption from seawater and study coordination chemistry of uranyl ion with those ligands in order to resolve current problems in uranium recovery technology from seawater and to develop novel selective and efficient adsorbents for this purpose.

Revisit the isospin violating decays of (3872)

Meng, L.*; Wang, G.-J.*; Wang, B.*; Zhu, S.-L.*

Physical Review D, 104(9), p.094003_1 - 094003_8, 2021/11

https://doi.org/10.1103/PhysRevD.104.094003

The isospin violating decays of are revisited in a coupled-channel effective field theory. In a cutoff-independent formalism, we relate the coupling constants of with the two channels to the molecular wave function. The isospin violating decays of are obtained by two equivalent approaches, which amend some deficiencies about this issue in literature. In the quantum field theory approach, the isospin violating decays arise from the coupling constants of to two di-meson channels. In the quantum mechanics approach, the isospin violating is attributed to wave functions at the origin. We bridge the isospin violating decays of to its inner structure. Our results show that the proportion of the neutral channel in is over 80%. As a by-product, we find that the strong decay width and radiative decay width are about 30 keV and 10 keV, respectively, for the binding energy from -300 keV to -50 keV.

Development of tailor-made adsorbents for uranium recovery from seawater on the basis of uranyl coordination chemistry (Contract research); FY2019 Nuclear Energy Science & Technology and Human Resource Development Project

Collaborative Laboratories for Advanced Decommissioning Science; Tokyo Institute of Technology*

JAEA-Review 2020-026, 41 Pages, 2020/12

JAEA-Review-2020-026.pdf:3.25MB

The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2019. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2019, this report summarizes the research results of the "Development of Tailor-Made Adsorbents for Uranium Recovery from Seawater on the Basis of Uranyl Coordination Chemistry". On the basis of deep understanding on uranyl coordination chemistry, we design molecular structures of pentadentate ligands as functional moieties for uranium adsorption from seawater and study coordination chemistry of uranyl ion with those ligands in order to resolve current problems in uranium recovery technology from seawater and to develop novel selective and efficient adsorbents for this purpose.

Survey of computational methods of cross sections for thermal neutron scattering by liquids

Ichihara, Akira

JAEA-Review 2019-046, 36 Pages, 2020/03

JAEA-Review-2019-046.pdf:1.55MB

Toward the revision of JENDL-4.0, we conducted a literature survey on how to compute the cross section of thermal neutrons scattered by a liquid. This report summarizes the computational methods for evaluating thermal neutron cross sections with molecular dynamics simulations. The cross section can be expressed with a function called as scattering law. For light and heavy water, the scattering law data instead of the cross sections have been provided in nuclear databases. In this report we review the formulations of the scattering laws. The scattering laws can be derived from both the intermediate scattering function and the space-time correlation function. Features of the derived scattering laws are briefly explained. It is shown that the scattering law data can be evaluated using a molecular dynamics simulation of the liquid that is the target of thermal neutrons.

Molecular dynamics simulations of physical properties of water and cations in montmorillonite interlayer; Application to diffusion model

Yotsuji, Kenji*; Tachi, Yukio; Kawamura, Katsuyuki*; Arima, Tatsumi*; Sakuma, Hiroshi*

Nendo Kagaku, 58(1), p.8 - 25, 2019/00

https://doi.org/10.11362/jcssjnendokagaku.58.1_8

Molecular dynamics (MD) simulations were conducted to investigate physical properties of water and cations in montmorillonite interlayer nanopores. The swelling behaviors and hydration states were firstly evaluated as functions of interlayer cations and layer charge. The diffusion coefficients of water and cations in interlayer nanopores were decreased in comparison with those in bulk water and came closer to those in bulk water when basal spacing increased. The viscosity coefficients of interlayer water estimated indicated a significant effect of viscoelectricity at 1- and 2-layer hydration states and higher layer charge of montmorillonite. These trends from MD calculations were confirmed to be consistent with existing measured data and previous MD simulation. In addition, model and parameter related to viscoelectric effect used in the diffusion model was refined based on comparative discussion between MD simulations and measurements. The series of MD calculations could provide atomic level understanding for the developments and improvements of the diffusion model for compacted montmorillonite.

Diffusion and adsorption of uranyl ion in clays; Molecular dynamics study

Arima, Tatsumi*; Idemitsu, Kazuya*; Inagaki, Yaohiro*; Kawamura, Katsuyuki*; Tachi, Yukio; Yotsuji, Kenji

Progress in Nuclear Energy, 92, p.286 - 297, 2016/09

https://doi.org/10.1016/j.pnucene.2016.03.006

Diffusion and adsorption behavior of uranyl (UO) species is important for the performance assessment of radioactive waste disposal. The diffusion behaviors of UO, K, CO and Cl and HO in the aqueous solutions were evaluated by molecular dynamics (MD) calculations. The diffusion coefficient (De) of UO is the smallest and is 26% less than the self-diffusion coefficient of HO. For the aqueous solution with high concentration of carbonate ions, uranyl carbonate complexes: UOCO and UO(CO) can be observed. For the clay (montmorillonite or illite)-aqueous solution systems, the adsorption and diffusion behaviors of UO and K were evaluated by MD calculations. The distribution coefficients (Kd) increase with the layer charge of clay, and Kd of UO might be smaller than that of K. Further, their two-dimensional diffusion coefficients were relatively small in the adsorption layer and were extremely small for illite with higher layer charge.

Corrigendum to "Real time observation of oxygen chemisorption states on Si(001)-21 during supersonic oxygen molecular beam irradiation"

Teraoka, Yuden; Yoshigoe, Akitaka

Applied Surface Science, 346, P. 580, 2015/08

https://doi.org/10.1016/j.apsusc.2015.02.145

Corrigendum to "Coexistence of passive and active oxidation for O/Si(001) system observed by SiO mass spectrometry and synchrotron radiation photoemission spectroscopy"

Teraoka, Yuden; Moritani, Kosuke*; Yoshigoe, Akitaka

Applied Surface Science, 343, P. 213, 2015/07

https://doi.org/10.1016/j.apsusc.2015.02.147

Corrigendum to "Commissioning of surface chemistry end-station in BL23SU of SPring-8" [Appl. Surf. Sci. 169-170 (2001) 738-741]

Teraoka, Yuden; Yoshigoe, Akitaka

Applied Surface Science, 339, P. 158, 2015/06

https://doi.org/10.1016/j.apsusc.2015.02.144