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Ikemoto H, Miyanaga T, Saiful Islam M, Kawaguchi R. Rigid covalent bond of α-sulfur investigated via temperature-dependent EXAFS. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:325704. [PMID: 38670081 DOI: 10.1088/1361-648x/ad442f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Accepted: 04/26/2024] [Indexed: 04/28/2024]
Abstract
This study performs extended x-ray absorption fine structure (EXAFS) measurements for the S-K edge in the temperature range of 10 and 300 K in the transmission mode using a photodiode to detect the transmitted x-rays. It provides the first report of temperature variations in the structural parameters ofα-S. As the temperature increases from 10 to 300 K in the Fourier transform ofkχ(k)the first peak corresponding to the covalent bond of the eight-membered ring becomes slightly low anomalously despite thermal disturbances. However, as in normal materials, the second peak at 300 K decreases to approximately half of that at 10 K, which contains several intra- and inter-ring correlations. All structural parameters of the covalent bond obtained by nonlinear least squares fitting exhibit missing temperature variations. A value of zero for the asymmetric parameter in the EXAFS (C3) implies that the potential of the covalent bond is symmetric, and the constant value of the mean square relative displacement (MSRD) with temperature implies that the potential is extremely high. The Einstein model fitting for the temperature variation in the MSRD yields an Einstein temperature of 942 K and force constant (K) of 405 N m-1. The value ofKis the largest among those of chalcogen elements.
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Affiliation(s)
- Hiroyuki Ikemoto
- Department of Physics, University of Toyama, Toyama 930-8555, Japan
| | - Takafumi Miyanaga
- Department of Mathematics and Physics, Hirosaki University, Hirosaki 036-8561, Japan
| | - Md Saiful Islam
- Department of Physics, University of Toyama, Toyama 930-8555, Japan
| | - Reo Kawaguchi
- Department of Physics, University of Toyama, Toyama 930-8555, Japan
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Extracting Local Symmetry of Mono-Atomic Systems from Extended X-ray Absorption Fine Structure Using Deep Neural Networks. Symmetry (Basel) 2021. [DOI: 10.3390/sym13061070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In recent years, neural networks have become a new method for the analysis of extended X-ray absorption fine structure data. Due to its sensitivity to local structure, X-ray absorption spectroscopy is often used to study disordered systems and one of its more interesting property is the sensitivity not only to pair distribution function, but also to three-body distribution, which contains information on the local symmetry. In this study, by considering the case of Ni, we show that by using neural networks, it is possible to obtain not only the radial distribution function, but also the bond angle distribution between the first nearest-neighbors. Additionally, by adding appropriate configurations in the dataset used for training, we show that the neural network is able to analyze also data from disordered phases (liquid and undercooled state), detecting small changes in the local ordering compatible with results obtained through other methods.
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Ikemoto H, Miyanaga T. Structure study of the chalcogens and chalcogenides by X-ray absorption fine structure. Z PHYS CHEM 2021. [DOI: 10.1515/zpch-2020-1627] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
In this review, we make a survey of the structure studies for the chalcogen elements and several chalcogenides in liquid, amorphous and nanosized state by using X-ray absorption fine structure (XAFS). The chalcogen elements have hierarchic structures; the chain structure constructed with the strong covalent bond as a primary structure, and the weaker interaction between chains as a secondary one. Existence of these two kinds of interactions induces exotic behaviors in the liquid, amorphous and nanosized state of the chalcogen and chalcogenides. XAFS is a powerful structure analysis technique for multi-element systems and the disordered materials, so it is suitable for the study of such as liquid, amorphous and nanosized mixtures. In section 2, the structures for the liquid state are discussed, which show the interesting semiconductor-metal transition depending on their temperatures and components. In section 3, the structure for the amorphous states are discussed. Especially, some of chalcogens and chalcogenides present the photostructural change, which is important industrial application. In section 4, the structures of nanosized state, nanoparticles and isolated chain confined into the narrow channel, are discussed. The studies of the nanoparticle and the isolated chain reveal the alternative role between the intrachain covalent bonds and the interchain interaction.
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Affiliation(s)
- Hiroyuki Ikemoto
- Department of Physics , University of Toyama , Toyama , 930-8555 , Japan
| | - Takafumi Miyanaga
- Department of Mathematics and Physics , Hirosaki University , Hirosaki , Aomori , 036-8561 , Japan
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Fast operando spectroscopy tracking in situ generation of rich defects in silver nanocrystals for highly selective electrochemical CO 2 reduction. Nat Commun 2021; 12:660. [PMID: 33510153 PMCID: PMC7844229 DOI: 10.1038/s41467-021-20960-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 01/05/2021] [Indexed: 01/31/2023] Open
Abstract
Electrochemical CO2 reduction (ECR) is highly attractive to curb global warming. The knowledge on the evolution of catalysts and identification of active sites during the reaction is important, but still limited. Here, we report an efficient catalyst (Ag-D) with suitable defect concentration operando formed during ECR within several minutes. Utilizing the powerful fast operando X-ray absorption spectroscopy, the evolving electronic and crystal structures are unraveled under ECR condition. The catalyst exhibits a ~100% faradaic efficiency and negligible performance degradation over a 120-hour test at a moderate overpotential of 0.7 V in an H-cell reactor and a current density of ~180 mA cm-2 at -1.0 V vs. reversible hydrogen electrode in a flow-cell reactor. Density functional theory calculations indicate that the adsorption of intermediate COOH could be enhanced and the free energy of the reaction pathways could be optimized by an appropriate defect concentration, rationalizing the experimental observation.
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Iesari F, Hatada K, Patel J, Balasubramanian C, Miyanaga T, Ikemoto H. Characterization of Te nanoparticles synthesized by plasma processing. Radiat Phys Chem Oxf Engl 1993 2020. [DOI: 10.1016/j.radphyschem.2019.05.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Ishito N, Nakajima K, Maegawa Y, Inagaki S, Fukuoka A. Facile formation of gold nanoparticles on periodic mesoporous bipyridine-silica. Catal Today 2017. [DOI: 10.1016/j.cattod.2017.03.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Fornasini P, Grisenti R. On EXAFS Debye-Waller factor and recent advances. JOURNAL OF SYNCHROTRON RADIATION 2015; 22:1242-1257. [PMID: 26289276 DOI: 10.1107/s1600577515010759] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 06/03/2015] [Indexed: 06/04/2023]
Abstract
The effects of structural and vibrational disorder on the EXAFS signals are parameterized in terms of the Debye Waller (DW) factor. Here the vibrational contribution is addressed, which for most systems can be singled out by studying the temperature dependence of the EXAFS DW factor, which corresponds to a good accuracy to the parallel mean square relative displacement (MSRD) around the inter-atomic equilibrium distance. By comparing the first-shell EXAFS thermal expansion with the crystallographic thermal expansion one can evaluate the perpendicular MSRD. The results of recent measurements on copper and on several tetrahedral semiconductors are here critically compared and some properties of the MSRDs are discussed, such as the dependence of correlation, force constants and vibrational anisotropy on crystal structure and bond ionicity as well as the relative merits of the correlated Debye and Einstein models. The anharmonic contribution to the parallel MSRD of CdTe has been evaluated and a quasi-harmonic analysis has been attempted, leading to an estimation of the bond Grüneisen parameter.
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Affiliation(s)
- P Fornasini
- Dipartimento di Fisica, Universita di Trento, I-38123 Povo, Trento, Italy
| | - R Grisenti
- Dipartimento di Fisica, Universita di Trento, I-38123 Povo, Trento, Italy
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Siqueira MC, Maia RNA, Araujo RMT, Machado KD, Stolf SF. Structural and thermal investigations of an amorphous GaSe9 alloy using EXAFS, cumulant expansion, and reverse Monte Carlo simulations. J Chem Phys 2015; 142:054504. [PMID: 25662651 DOI: 10.1063/1.4907280] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In this article, we investigated structural and thermal properties of an amorphous alloy of the Ga-Se system. The amorphous GaSe9 alloy was produced by mechanical alloying and it was studied using EXAFS spectroscopy and cumulant expansion method. We also made reverse Monte Carlo simulations using the total structure factor S(K) obtained from x-ray diffraction and the EXAFS χ(k) oscillations on Se and Ga K edges as input data. Several parameters, such as average coordination numbers and interatomic distances, structural and thermal disorders, asymmetry of the partial distribution functions gij(r), and Einstein and Debye temperatures, were determined. The gij (E)(r) functions were reconstructed from the cumulants C1, C2, and C3 obtained from the Einstein model, and they were compared to the gij (RMC)(r) functions obtained from the simulations. The simulations also furnished the partial bond angle distribution functions Θijℓ(cosθ), which describe the angular distribution of bonds between first neighbors, and give information about the kind of structural units present in the alloy.
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Affiliation(s)
- M C Siqueira
- Departamento de Física, Centro Politécnico, Universidade Federal do Paraná, 81531-990 Curitiba, Paraná, Brazil
| | - R N A Maia
- Departamento de Física, Centro Politécnico, Universidade Federal do Paraná, 81531-990 Curitiba, Paraná, Brazil
| | - R M T Araujo
- Departamento de Física, Centro Politécnico, Universidade Federal do Paraná, 81531-990 Curitiba, Paraná, Brazil
| | - K D Machado
- Departamento de Física, Centro Politécnico, Universidade Federal do Paraná, 81531-990 Curitiba, Paraná, Brazil
| | - S F Stolf
- Centro de Engenharia e Ciências Exatas, UNIOESTE, 85903-000 Toledo, Paraná, Brazil
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Ikemoto H, Miyanaga T. Local structure of amorphous tellurium studied by EXAFS. JOURNAL OF SYNCHROTRON RADIATION 2014; 21:409-412. [PMID: 24562563 DOI: 10.1107/s1600577513032748] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 12/02/2013] [Indexed: 06/03/2023]
Abstract
The local structure of an amorphous tellurium (a-Te) film was investigated by extended X-ray absorption fine-structure analysis. The covalent bond length shortens and the Debye-Waller factor of the intra-chain decreases in a-Te compared with trigonal Te (t-Te). The value of the intra-chain coordination number is close to two, which is the value for t-Te, and the inter-chain interaction weakens. These results suggest that the primary chain structure remains intact, but the secondary structure is disrupted. The decrease in the inter-chain interaction strengthens the intra-chain interaction.
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Affiliation(s)
- Hiroyuki Ikemoto
- Department of Physics, University of Toyama, Toyama 930-8555, Japan
| | - Takafumi Miyanaga
- Department of Advanced Physics, Hirosaki University, Hirosaki 036-8561, Japan
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Kassem M, Khaoulani S, Cuisset A, Le Coq D, Masselin P, Bychkov E. Mercury thioarsenate glasses: a hybrid chain/pyramidal network. RSC Adv 2014. [DOI: 10.1039/c4ra07811j] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Mercury thioarsenate glasses (HgS)x(As2S3)1−x, 0.0 ≤x≤ 0.5, form a hybrid (HgS2/2)nchain/AsS3/2pyramidal network, highly unusual for metal chalcogenide glasses. This network is evidenced by Raman spectroscopy and DFT modelling and consistent with thermal properties. Nevertheless we cannot exclude completely the presence of a small fraction of HgS4/4tetrahedral units.
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Affiliation(s)
- Mohammad Kassem
- Univ Lille Nord de France
- F-59000 Lille, France
- ULCO
- LPCA, EA CNRS 4493
- F-59140 Dunkerque, France
| | - Sohayb Khaoulani
- Univ Lille Nord de France
- F-59000 Lille, France
- ULCO
- LPCA, EA CNRS 4493
- F-59140 Dunkerque, France
| | - Arnaud Cuisset
- Univ Lille Nord de France
- F-59000 Lille, France
- ULCO
- LPCA, EA CNRS 4493
- F-59140 Dunkerque, France
| | - David Le Coq
- Sciences Chimiques de Rennes
- UMR CNRS 6226
- Eq. Verres et Céramiques
- Univ. de Rennes I
- F-35042 Rennes, France
| | - Pascal Masselin
- Univ Lille Nord de France
- F-59000 Lille, France
- ULCO
- LPCA, EA CNRS 4493
- F-59140 Dunkerque, France
| | - Eugene Bychkov
- Univ Lille Nord de France
- F-59000 Lille, France
- ULCO
- LPCA, EA CNRS 4493
- F-59140 Dunkerque, France
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Kostrzepa IM, Siqueira MC, Machado KD, Maciel GA, Sanchez DF, Brunatto SF. Structural investigations on an amorphous Se90Te10 alloy produced by mechanical alloying using EXAFS, cumulant expansion and RMC simulations. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:125401. [PMID: 22371432 DOI: 10.1088/0953-8984/24/12/125401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We investigated an amorphous Se(90)Te(10) alloy produced by mechanical alloying using two different approaches. First, we used extended x-ray absorption fine structure (EXAFS) spectroscopy and the cumulant expansion method using the Einstein model for the temperature dependence of the cumulants to obtain the cumulants C(*)(1), C(*)(2), and C(*)(3). From these, we found information about the structure of the alloy as well as the thermal and structural disorder, anharmonicity of the effective interatomic pair potentials, thermal expansion of the Se-Se and Se-Te bonds and asymmetry of the partial distribution functions g(Se-Se)(r) and g(Se-Te)(r). The cumulants C(*)(1), C(*)(2), and C(*)(3) also allowed us to reconstruct the g(EXAFS)(ij)(r,T) functions from EXAFS. Then, we made reverse Monte Carlo (RMC) simulations using the total structure factor S(K) obtained from synchrotron x-ray diffraction and the EXAFS oscillations χ(k) on the Se K edge as input data to obtain the g(RMC)(ij)(r) functions. Both methods furnished very similar g(ij)(r) functions, and the structural data obtained from them were also very similar. The results obtained from both methods showed the presence of Se-Te pairs indicating that there is alloying at the atomic level. In addition, we could not find any evidence of the presence of Te clusters in the alloy.
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Affiliation(s)
- I M Kostrzepa
- Departamento de Física, Centro Politécnico, Universidade Federal do Paraná, 81531-990, Curitiba, Paraná, Brazil
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Machado KD. Comparison between Einstein and Debye models for an amorphous Ni46Ti54alloy produced by mechanical alloying investigated using extended x-ray absorption fine structure and cumulant expansion. J Chem Phys 2011; 134:064503. [DOI: 10.1063/1.3533960] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Dubiel M, Haug J, Kruth H, Hofmeister H, Seifert W. Temperature dependence of EXAFS cumulants of Ag nanoparticles in glass. ACTA ACUST UNITED AC 2009. [DOI: 10.1088/1742-6596/190/1/012123] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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