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Butorin, Sergei
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Publications (10 of 47) Show all publications
Butorin, S. M. M., Kvashnina, K. O., Prieur, D., Rivenet, M. & Martin, P. M. (2017). Characteristics of chemical bonding of pentavalent uranium in La-doped UO2. Chemical Communications, 53(1), 115-118
Open this publication in new window or tab >>Characteristics of chemical bonding of pentavalent uranium in La-doped UO2
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2017 (English)In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 53, no 1, p. 115-118Article in journal (Refereed) Published
Abstract [en]

The effect of La doping on the electronic structure of U in UO2 was studied using an advanced technique, namely, X-ray absorption spectroscopy (XAS) in the high-energy-resolution fluorescence-detection (HERFD) mode, at the U 3d(3/2) (M-4) edge. Thanks to a significant reduction of the core-hole lifetime broadening and distinct chemical shifts of the HERFD-XAS lines, the U(v) formation as a result of La doping was identified. The isolated contribution of U(v) in the M-4 HERFD-XAS spectrum reveals the so-called charge-transfer satellites due to the U 5f-O 2p hybridization. The analysis of the experimental data within the framework of the Anderson impurity model (AIM) indicates a significant change in the characteristics and degree of covalency for the chemical bonding in the U(v) subsystem of UO2 as compared to undoped UO2, which is a Mott-Hubbard system. The results are also supported by AIM calculations of X-ray photoelectron and optical absorption data.

National Category
Chemical Sciences
Identifiers
urn:nbn:se:uu:diva-315832 (URN)10.1039/c6cc07684j (DOI)000391607100012 ()
Available from: 2017-02-21 Created: 2017-02-21 Last updated: 2017-11-29Bibliographically approved
Conradson, S. D., Andersson, D. A., Boland, K. S., Bradley, J. A., Byler, D. D., Durakiewicz, T., . . . Tayal, A. (2017). Closure of the Mott gap and formation of a superthermal metal in the Frohlich-type nonequilibrium polaron Bose-Einstein condensate in UO2+x. Physical Review B, 96(12), Article ID 125114.
Open this publication in new window or tab >>Closure of the Mott gap and formation of a superthermal metal in the Frohlich-type nonequilibrium polaron Bose-Einstein condensate in UO2+x
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2017 (English)In: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 96, no 12, article id 125114Article in journal (Refereed) Published
Abstract [en]

Mixed valence O-doped UO2+x. and photoexcited UO2 containing transitory U3+ and U5+ host a coherent polaronic quantum phase (CPQP) that exhibits the characteristics of a Frohlich-type, nonequilibrium, phononcoupled Bose-Einstein condensate whose stability and coherence are amplified by collective, anharmonic motions of atoms and charges. Complementary to the available, detailed, real space information from scattering and EXAFS, an outstanding question is the electronic structure. Mapping the Mott gap in UO2, U4O9, and U3O7 with O XAS and NIXS and UM5 RIXS shows that O doping raises the peak of the U5f states of the valence band by similar to 0.4 eV relative to a calculated value of 0.25 eV. However, it lowers the edge of the conduction band by 1.5 eV vs the calculated 0.6 eV, a difference much larger than the experimental error. This 1.9 eV reduction in the gap width constitutes most of the 2-2.2 eV gap measured by optical absorption. In addition, the XAS spectra show a tail that will intersect the occupied U5f states and give a continuous density-of-states that increases rapidly above its constricted intersection. Femtosecond-resolved photoemission measurements of UO2, coincident with the excitation pulse with 4.7 eV excitation, show the unoccupied U5f states of UO2 and no hot electrons. 3.1 eV excitation, however, complements the O-doping results by giving a continuous population of electrons for several eV above the Fermi level. The CPQP in photoexcited UO2 therefore fulfills the criteria for a nonequilibrium condensate. The electron distributions resulting from both excitations persist for 5-10 ps, indicating that they are the final state that therefore forms without passing through the initial continuous distribution of nonthermal electrons observed for other materials. Three exceptional findings are: (1) the direct formation of both of these long lived (> 3-10 ps) excited states without the short lived nonthermal intermediate; (2) the superthermal metallic state is as or more stable than typical photoinduced metallic phases; and (3) the absence of hot electrons accompanying the insulating UO2 excited state. This heterogeneous, nonequilibrium, Frohlich BEC stabilized by a Fano-Feshbach resonance therefore continues to exhibit unique properties.

National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-335203 (URN)10.1103/PhysRevB.96.125114 (DOI)000410002000004 ()
Available from: 2017-12-06 Created: 2017-12-06 Last updated: 2017-12-06Bibliographically approved
Safdari, M., Phuyal, D., Philippe, B., Svensson, P. H., Butorin, S., Kvashnina, K. O., . . . Gardner, J. M. (2017). Impact of synthetic routes on the structural and physical properties of butyl-1,4-diammonium lead iodide semiconductors. Journal of Materials Chemistry A, 5(23), 11730-11738
Open this publication in new window or tab >>Impact of synthetic routes on the structural and physical properties of butyl-1,4-diammonium lead iodide semiconductors
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2017 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 5, no 23, p. 11730-11738Article in journal (Refereed) Published
Abstract [en]

We report the significant role of synthetic routes and the importance of solvents in the synthesis of organic-inorganic lead iodide materials. Through one route, the intercalation of dimethylformamide in the crystal structure was observed leading to a one-dimensional (1D) [NH3(CH2)(4)NH3]Pb2I6 structure of the product. This product was compared with the two-dimensional (2D) [NH3(CH2)(4)NH3]PbI4 recovered from aqueous solvent based synthesis with the same precursors. UV-visible absorption spectroscopy showed a red-shift of 0.1 eV for the band gap of the 1D network in relation to the 2D system. This shift primarily originates from a shift in the valence band edge as determined from photoelectron-and X-ray spectroscopy results. These findings also suggest the iodide 5p orbital as the principal component in the density of states in the valence band edge. Single crystal data show a change in the local coordination around iodide, while in both materials, lead atoms are surrounded by iodide atoms in octahedral units. The conductivity of the one-dimensional material ([NH3(CH2)(4)NH3]Pb2I6) was 50% of the two-d(i)mensional material ([NH3(CH2)(4)NH3]PbI4). The fabricated solar cells reflect these changes in the chemical and electronic structure of both materials, although the total light conversion efficiencies of solar cells based on both products were similar.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2017
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-329653 (URN)10.1039/c6ta10123b (DOI)000403228200030 ()
Funder
StandUpSwedish Energy AgencySwedish Research CouncilKnut and Alice Wallenberg Foundation
Available from: 2017-09-20 Created: 2017-09-20 Last updated: 2017-09-20Bibliographically approved
Butorin, S. M., Modin, A., Vegelius, J. R., Suzuki, M.-T., Oppeneer, P. M., Andersson, D. A. & Shuh, D. K. (2016). Local Symmetry Effects in Actinide 4f X-ray Absorption in Oxides. Analytical Chemistry, 88(8), 4169-4173
Open this publication in new window or tab >>Local Symmetry Effects in Actinide 4f X-ray Absorption in Oxides
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2016 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 88, no 8, p. 4169-4173Article in journal (Refereed) Published
Abstract [en]

A systematic X-ray absorption study at actinide N-6,(7) (4f -> 6d transitions) edges was performed for light-actinide oxides including data obtained for the first time for NpO2, PuO2 and UO3. The measurements were supported by ab initio calculations based on local-density approximation. with added 5f-5f Coulomb interaction (LDA+U). Improved energy resolution compared to common experiments at actinide L-2,L-3 (2p -> 6d transitions) edges allowed us to resolve the major structures of the 13 unoccupied 6d density of states (DOS) and estimate the crystal-field 116) splittings in the 6d shell directly from the spectra of light-actinide dioxides. The measurements demonstrated an enhanced sensitivity of the N-6,N-7, spectral shape to changes in the compound crystal structure. For nonstoichiometric NpO2-x, the filling of the entire band gap with Np 6d states was observed thus supporting a phase coexistence of Np metal and stoichiometric NpO2 which is in agreement with the tentative Np-O phase diagram.

National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-297906 (URN)10.1021/acs.analchem.5b04380 (DOI)000374706000001 ()27008406 (PubMedID)
Funder
Swedish Research CouncilEU, FP7, Seventh Framework Programme, 269903Swedish National Infrastructure for Computing (SNIC)
Available from: 2016-06-29 Created: 2016-06-28 Last updated: 2017-11-28Bibliographically approved
Butorin, S. M. M., Modin, A., Vegelius, J., Kvashnina, K. O. & Shuh, D. K. (2016). Probing Chemical Bonding in Uranium Dioxide by Means of High- Resolution X-ray Absorption Spectroscopy. The Journal of Physical Chemistry C, 120(51), 29397-29404
Open this publication in new window or tab >>Probing Chemical Bonding in Uranium Dioxide by Means of High- Resolution X-ray Absorption Spectroscopy
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2016 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 120, no 51, p. 29397-29404Article in journal (Refereed) Published
Abstract [en]

A systematic X-ray absorption study at the U 3d, 4d, and 4f edges of UO2 was performed, and the data were analyzed within framework of the Anderson impurity model. By applying the high-energy-resolution fluorescence-detection (HERFD) mode of X-ray absorption spectroscopy (XAS) at the U 3d(3/2) edge and conducting the XAS measurements at the shallower U 4f levels, fine details of the XAS spectra were resolved resulting from reduced core-hole lifetime broadening. This multiedge study enabled a far more effective analysis of the electronic structure at the U sites and characterization of the chemical bonding and degree of the 5f localization in UO2. The results support the covalent character of UO2 and do not agree with the suggestions of rather ionic bonding in this compound as expressed in some publications.

National Category
Atom and Molecular Physics and Optics
Identifiers
urn:nbn:se:uu:diva-315073 (URN)10.1021/acs.jpcc.6b09335 (DOI)000391160400052 ()
Available from: 2017-02-10 Created: 2017-02-10 Last updated: 2017-11-29Bibliographically approved
Modin, A., Suzuki, M.-T., Vegelius, J., Yun, Y., Shuh, D. K., Werme, L., . . . Butorin, S. M. (2015). 5 f-Shell correlation effects in dioxides of light actinides studied by O 1s x-ray absorption and emission spectroscopies and first-principles calculations. Journal of Physics: Condensed Matter, 27(31), Article ID 315503.
Open this publication in new window or tab >>5 f-Shell correlation effects in dioxides of light actinides studied by O 1s x-ray absorption and emission spectroscopies and first-principles calculations
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2015 (English)In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 27, no 31, article id 315503Article in journal (Refereed) Published
Abstract [en]

Soft x-ray emission and absorption spectroscopic data are reported for the O 1s region of a single crystal of UO2, a polycrystalline NpO2 sample, and a single crystal of PuO2. The experimental data are interpreted using first-principles correlated-electron calculations within the framework of the density functional theory with added Coulomb U interaction (DFT+U). A detailed analysis regarding the origin of different structures in the x-ray emission and x-ray absorption spectra is given and the effect of varying the intra-atomic Coulomb interaction-U for the 5f electrons is investigated. Our data indicate that O 1s x-ray absorption and emission spectroscopies can, in combination with DFT+U calculations, successfully be used to study 5f-shell Coulomb correlation effects in dioxides of light actinides. The values for the Coulomb U parameter in these dioxides are derived to be in the range of 4-5 eV.

Keywords
actinide dioxides, x-ray spectroscopy, DFT plus U
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-260803 (URN)10.1088/0953-8984/27/31/315503 (DOI)000358595500007 ()26202182 (PubMedID)
Funder
Swedish Research Council
Available from: 2015-08-31 Created: 2015-08-25 Last updated: 2017-12-04Bibliographically approved
Kvashnina, K., Kvashnin, Y., Vegelius, J. R., Bosak, A., Martin, P. M. & Butorin, S. M. (2015). Sensitivity to Actinide Doping of Uranium Compounds by Resonant Inelastic X-ray Scattering at Uranium L-3 Edge. Analytical Chemistry, 87(17), 8772-8780
Open this publication in new window or tab >>Sensitivity to Actinide Doping of Uranium Compounds by Resonant Inelastic X-ray Scattering at Uranium L-3 Edge
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2015 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 87, no 17, p. 8772-8780Article in journal (Refereed) Published
Abstract [en]

Valence-to-core resonant inelastic X-ray scattering (RIXS) and high energy resolution fluorescence detection (HERFD) X-ray absorption measurements were performed at the U (L)3 edges of UO2 and UO2(NO3)(2)(H2O)(6). The results are compared with model calculations based on the local-density-approximation formalism, taking into account Coulomb interaction U (LDA + U). We show that despite strong 5f-5f electronic correlations in the studied systems and the use of core-level excitations in the intermediate stage of the spectroscopic process, the RIXS technique probes a convolution of the single-particle densities of states in the valence and conduction bands. For UO2, the detected crystal-field splitting between the U 6d e(g) and t(2g) orbitals from the RIXS spectra (similar to 3.5 eV) is larger than that previously derived from optical spectroscopy. Furthermore, by using an example of the U0.75Pu0.25O2 mixed oxide, we show that the RIXS technique at the U L-3 edges is sensitive to the substitution of U with other actinide, in contrast to conventional X-ray absorption methods. That is, due to changes in the occupied part rather than in the unoccupied part of the U 6d states caused by the substitution.

National Category
Chemical Sciences
Identifiers
urn:nbn:se:uu:diva-264057 (URN)10.1021/acs.analchem5b01699 (DOI)000360773100027 ()26255719 (PubMedID)
Available from: 2015-10-05 Created: 2015-10-05 Last updated: 2017-12-01Bibliographically approved
Kvashnina, K. O., Kvashnin, Y. & Butorin, S. (2014). Role of resonant inelastic X-ray scattering in high-resolution core-level spectroscopy of actinide materials. Journal of Electron Spectroscopy and Related Phenomena, 194, 27-36
Open this publication in new window or tab >>Role of resonant inelastic X-ray scattering in high-resolution core-level spectroscopy of actinide materials
2014 (English)In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 194, p. 27-36Article in journal (Refereed) Published
Abstract [en]

This paper provides a brief overview of applications of advanced X-ray spectroscopic techniques that take advantage of the resonant inelastic X-ray scattering (RIXS) in the hard and tender X-ray range and have recently become available for studying the electronic structure of actinides. We focus here on the high-energy-resolution X-ray absorption near edge structure (XANES) and core-to-core and core-to-valence RIXS spectroscopies at the U L and M edges of uranium compounds. The spectral features are analyzed using a number of theoretical methods, such as the Anderson impurity model, density functional theory in the local density approximation with an added Coulomb interaction (LDA + U), and full multiple scattering (FEFF) and ab initio finite difference method near-edge structure (FDMNES) codes. In connection with presented results, the capabilities and limitations of the experimental techniques and theoretical methods are discussed. (C) 2014 Elsevier B.V. All rights reserved.

Keywords
Actinides, X-ray spectroscopy, XANES, RIXS, Electronic structure
National Category
Physical Sciences
Identifiers
urn:nbn:se:uu:diva-230526 (URN)10.1016/j.elspec.2014.01.016 (DOI)000339040000006 ()
Available from: 2014-08-28 Created: 2014-08-26 Last updated: 2017-12-05Bibliographically approved
Shuh, D. K., Batista, E. R., Butorin, S. M., Clark, D. L., Guo, J., Keith, J. M., . . . Tyliszczak, T. (2013). Actinide science the Richard G. Haire way: Inspiring, innovative, energetic, and sleeves-up. Paper presented at 245th National Spring Meeting of the American-Chemical-Society (ACS), APR 07-11, 2013, New Orleans, LA, USA. Abstract of Papers of the American Chemical Society, 245, 48-NUCL
Open this publication in new window or tab >>Actinide science the Richard G. Haire way: Inspiring, innovative, energetic, and sleeves-up
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2013 (English)In: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 245, p. 48-NUCL-Article in journal, Meeting abstract (Other academic) Published
National Category
Natural Sciences
Identifiers
urn:nbn:se:uu:diva-210344 (URN)000324303602646 ()
Conference
245th National Spring Meeting of the American-Chemical-Society (ACS), APR 07-11, 2013, New Orleans, LA, USA
Available from: 2013-11-06 Created: 2013-11-05 Last updated: 2017-12-06Bibliographically approved
Butorin, S. M., Shuh, D. K., Kvashnina, K. O., Guo, J., Werme, L. & Nordgren, J. (2013). Chemical Reduction of Actinides Probed by Resonant Inelastic X-ray Scattering. Analytical Chemistry, 85(23), 11196-11200
Open this publication in new window or tab >>Chemical Reduction of Actinides Probed by Resonant Inelastic X-ray Scattering
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2013 (English)In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 85, no 23, p. 11196-11200Article in journal (Refereed) Published
Abstract [en]

The study addresses the possibilities of immobilizing the mobile species of actinides in the geosphere using metallic iron. Sorption on corroding iron is well-known, but there have been uncertainties with regard to the possibilities of reducing the actinyl species to sparingly soluble oxides and, thereby, permanently immobilizing them. Resonant inelastic X-ray scattering (RIXS) measurements at the actinide 5d edges on Fe foils exposed to uranium(VI) and neptunium(V) solutions in groundwater unambigiously indicate reduction of actinides to, respectively, uranium(IV) and neptunium(IV) on iron surfaces. The reduction manifests itself in an appearance of distinct specific signatures of uranium(IV) and neptunium(IV) in the RIXS profile of 5f-5f excitations. Such signatures and RIXS intensity/cross-section behavior with varying energy of incident photons can be reproduced by model atomic-multiplet calculations of the RIXS spectra. By normalizing the RIXS signal of corresponding 5f-5f excitations to core-to-core 6p-to-5d characteristic fluorescence transitions of actinides, their reduction rates on Fe samples with different exposure to actinide solutions can be estimated. Observed reduction implies similar processes in the nuclear waste canister thus suggesting reduced probability of nuclear waste release with ground waters from the canister.

National Category
Natural Sciences
Identifiers
urn:nbn:se:uu:diva-214022 (URN)10.1021/ac4020534 (DOI)000327999800007 ()
Available from: 2014-01-07 Created: 2014-01-07 Last updated: 2017-12-06Bibliographically approved
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