An X-ray and neutron scattering study of aqueous MgCl solution in the gigapascal pressure range

Yamaguchi, Toshio*; Fukuyama, Nami*; Yoshida, Koji*; Katayama, Yoshinori*; Machida, Shinichi*; Hattori, Takanori

Liquids, 3(3), p.288 - 302, 2023/09

https://doi.org/10.3390/liquids3030019

We report the structure of an aqueous 2 mol/kg MgCl solution at pressures from 0.1 MPa to 4 GPa and temperatures from 300 to 500 K revealed by X-ray and neutron scattering measurements. The scattering data are analyzed by empirical potential structure refinement (EPSR) modeling to derive the pair distribution functions, coordination number distributions, angle distributions, and spatial density functions as a function of pressure and temperature. Mg forms rigid solvation shells extended to the third shell; the first solvation shell of six-fold octahedral coordination with about six water molecules at 0 GPa transforms into about five water molecules and one Cl due to the formation of the contact ion pairs in the GPa pressure range. The Cl solvation shows a substantial pressure dependence; the coordination number of a water oxygen atom around Cl increases from 8 at 0.1 MPa/300 K to 10 at 4 GPa/500 K. The solvent water transforms the tetrahedral network structure at 0.1 MPa/300 K to a densely packed structure in the GPa pressure range; the number of water oxygen atoms around a central water molecule gradually increases from 4.6 at 0.1 MPa/298 K to 8.4 at 4 GPa/500 K.

A Hybrid framework of first principles molecular orbital calculations and a three-dimensional integral equation theory for molecular liquids; Multi-center molecular Ornstein-Zernike self-consistent field approach

Kido, Kentaro; Kasahara, Kento*; Yokogawa, Daisuke*; Sato, Hirofumi*

Journal of Chemical Physics, 143(1), p.014103_1 - 014103_9, 2015/07

https://doi.org/10.1063/1.4923007

Role of trapped and solvated electrons in Ps formation

Stepanov, S. V.*; Byakov, V. M.*; He, C.*; Hirade, Tetsuya; Mikhin, K. V.*

Acta Physica Polonica A, 107(4), p.642 - 650, 2005/00

http://przyrbwn.icm.edu.pl/APP/PDF/107/a107z414.pdf

Role of trapped and solvated electrons in Ps formation is discussed. Combination of thermalized positron with such electrons is energetically possible and may contribute to Ps formation. Contrary to the positron reaction with a quasi-free electron, this process is not limited to picosecond times, but proceeds on a timescale of nanoseconds. In this case conventional exponential deconvolution of row lifetime positron annihilation spectra becomes questionable. Rigorous treatment of the data needs nonexponential deconvolution, based on an adequate physical input. Such an approach is suggested here. Its reduced form is used for interpretation of the Ps formation data in polyethylene, EMMA and PMMA in dark and in light vs. time of the measurement and temperature. Parameters characterized accumulation of trapped electrons and their recombination with counter ions and positrons are obtained.

Luminescence study on preferential solvation of europium (III) in water/non-aqueous solvent mixtres

Kimura, Takaumi; Nagaishi, Ryuji; Kato, Yoshiharu; Yoshida, Zenko

Journal of Alloys and Compounds, 323-324(1-4), p.164 - 168, 2001/07

https://doi.org/10.1016/S0925-8388(01)01121-5

no abstracts in English

Application of time-resolved fluorescence spectroscopy to supercritical fluid study

Kimura, Takaumi

Bunseki, (291), p.246 - 247, 1999/00

no abstracts in English

Emission and excitation spectra of silver atoms in -irradiated aqueous, ethanol, and 2-methyltetrahydrofuran solutions at 77K

*; *; *; ; Arai, Shigeyoshi*

Radiation Physics and Chemistry, 49(1), p.59 - 65, 1997/00

https://doi.org/10.1016/S0969-806X(96)00107-7

no abstracts in English

Development of a hybrid framework of first principle molecular orbital calculations and a three-dimensional integral equation theory for molecular liquids (MC-MOZ method)

Kido, Kentaro; Kasahara, Kento*; Sato, Hirofumi*; Yokogawa, Daisuke*

no journal, , 

We develop a framework to describe chemical processes in solution by combining of standard MO calculation and a three-dimensional formalism of integral equation theory for molecular liquids so-called MC-MOZ method, which corresponds to an alternative 3D-RISM-SCF approach. In order to investigate the validity, the applications to water and formaldehyde in aqueous solution are carried out. Compared with the related frameworks and experimental values, the solvation structures, electronic and thermodynamic properties obtained by the present method are reasonable. Similarly, the present framework was applied to a simple chemical reaction.