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| 2. |
- Jahnke, T., et al.
(författare)
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Inner-Shell-Ionization-Induced Femtosecond Structural Dynamics of Water Molecules Imaged at an X-Ray Free-Electron Laser
- 2021
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Ingår i: Physical Review X. - : American Physical Society. - 2160-3308. ; 11:4
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Tidskriftsartikel (refereegranskat)abstract
- The ultrafast structural dynamics of water following inner-shell ionization is a crucial issue in high-energy radiation chemistry. We have exposed isolated water molecules to a short x-ray pulse from a free-electron laser and detected momenta of all produced ions in coincidence. By combining experimental results and theoretical modeling, we can image dissociation dynamics of individual molecules in unprecedented detail. We reveal significant molecular structural dynamics in H2O2+, such as asymmetric deformation and bond-angle opening, leading to two-body or three-body fragmentation on a timescale of a few femtoseconds. We thus reconstruct several snapshots of structural dynamics at different time intervals, which highlight dynamical patterns that are relevant as initiating steps of subsequent radiation-damage processes.
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| 3. |
- Bagriy, I.D., et al.
(författare)
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H2 - Ecological source of decarbonization - The path to energy independence of Ukraine
- 2023
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- The research studied the pressing problem of the fuel and energy strategy of the XXI century. For the first time, there was shown the diversity of the authors' approach to theoretical and applied problems of hydrogen energy. General issues of fundamental and applied aspects of hydrogen origin were covered. The study provides the results of scientific developments on hydrogen mapping performed within the framework of scientific and practical exploratory and geo-ecological research on more than 200 hydrocarbon objects both on land (including mining fields) and in marine water areas. Prognostic and search system criteria were substantiated, with hydrogen being used for the first time as a component of the complex of methodical solutions in the search practice. The research showed the importance of solving the problem of geo-ecological processes and accidents in mine workings and wells, connected to numerous disasters. According to numerous studies of mine massives, a set of preventive measures and criteria that prevent explosive processes was provided.The presence of a unique complex of natural components of hydrogen technology, solar and wind energy resources and fresh waters of the Danube lakes and the Danube was stated.The study emphasises the decisive role of Ukraine in the competition for primacy in scientific developments. For the first time in world practice, the implementation of global projects for the extraction and production of green and white hydrogen was substantiated.The technology was tested on numerous hydrocarbon deposits, water resources and mine workings and therefore has all the prospects for the effective application in the search and extraction of hydrogen. This monograph can be useful and informative for specialists in the fields of oil and gas geology, general and regional geology, hydrology, environmental protection, as well as for the students and postgraduate students of fuel and energy, oil and gas geological and hydrological areas, as well as for domestic and foreign investors.
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| 4. |
- Bagriy, I.D., et al.
(författare)
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H2 - ENVIRONMENTAL AND ENERGY CHALLENGESOF THE XXI CENTURY. GLOBAL PROJECTSWAYS OF IMPLEMENTATION
- 2023
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Bok (refereegranskat)abstract
- The research studied the pressing problem of the fuel and energy strategy of the XXI century. For the first time, there was shown the diversity of the authors' approach to theoretical and applied problems of hydrogen energy. General issues of fundamental and applied aspects of hydrogen origin were covered. The study provides the results of scientific developments on hydrogen mapping performed within the framework of scientific and practical exploratory and geo-ecological research on more than 200 hydrocarbon objects both on land (including mining fields) and in marine water areas. Prognostic and search system criteria were substantiated, with hydrogen being used for the first time as a component of the complex of methodical solutions in the search practice. The research showed the importance of solving the problem of geo-ecological processes and accidents in mine workings and wells, connected to numerous disasters. According to numerous studies of mine massives, a set of preventive measures and criteria that prevent explosive processes was provided. The presence of a unique complex of natural components of hydrogen technology, solar and wind energy resources and fresh waters of the Danube lakes and the Danube was stated. The study emphasises the decisive role of Ukraine in the competition for primacy in scientific developments. For the first time in world practice, the implementation of global projects for the extraction and production of green and white hydrogen was substantiated. The technology was tested on numerous hydrocarbon deposits, water resources and mine workings and therefore has all the prospects for the effective application in the search and extraction of hydrogen. This monograph can be useful and informative for specialists in the fields of oil and gas geology, general and regional geology, hydrology, environmental protection, as well as for the students and postgraduate students of fuel and energy, oil and gas geological and hydrological areas, as well as for domestic and foreign investors.
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| 5. |
- Borne, Kurtis D., et al.
(författare)
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Ultrafast electronic relaxation pathways of the molecular photoswitch quadricyclane
- 2024
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Ingår i: NATURE CHEMISTRY. - 1755-4330 .- 1755-4349. ; 16, s. 499-505
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Tidskriftsartikel (refereegranskat)abstract
- The light-induced ultrafast switching between molecular isomers norbornadiene and quadricyclane can reversibly store and release a substantial amount of chemical energy. Prior work observed signatures of ultrafast molecular dynamics in both isomers upon ultraviolet excitation but could not follow the electronic relaxation all the way back to the ground state experimentally. Here we study the electronic relaxation of quadricyclane after exciting in the ultraviolet (201 nanometres) using time-resolved gas-phase extreme ultraviolet photoelectron spectroscopy combined with non-adiabatic molecular dynamics simulations. We identify two competing pathways by which electronically excited quadricyclane molecules relax to the electronic ground state. The fast pathway (<100 femtoseconds) is distinguished by effective coupling to valence electronic states, while the slow pathway involves initial motions across Rydberg states and takes several hundred femtoseconds. Both pathways facilitate interconversion between the two isomers, albeit on different timescales, and we predict that the branching ratio of norbornadiene/quadricyclane products immediately after returning to the electronic ground state is approximately 3:2.
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| 6. |
- Cheng, Yu Chen, et al.
(författare)
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Imaging multiphoton ionization dynamics of CH3I at a high repetition rate XUV free-electron laser
- 2021
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Ingår i: Journal of Physics B-Atomic Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 54:1
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Tidskriftsartikel (refereegranskat)abstract
- XUV multiphoton ionization of molecules is commonly used in free-electron laser experiments to study charge transfer dynamics. However, molecular dissociation and electron dynamics, such as multiple photon absorption, Auger decay, and charge transfer, often happen on competing time scales, and the contributions of individual processes can be difficult to unravel. We experimentally investigate the Coulomb explosion dynamics of methyl iodide upon core-hole ionization of the shallow inner-shell of iodine (4d) and classically simulate the fragmentation by phenomenologically introducing ionization dynamics and charge transfer. Under our experimental conditions with medium fluence and relatively long XUV pulses (similar to 75 fs), we find that fast Auger decay prior to charge transfer significantly contributes to the charging mechanism, leading to a yield enhancement of higher carbon charge states upon molecular dissociation. Furthermore, we argue for the existence of another charging mechanism for the weak fragmentation channels leading to triply charged carbon atoms. This study shows that classical simulations can be a useful tool to guide the quantum mechanical description of the femtosecond dynamics upon multiphoton absorption in molecular systems.
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| 7. |
- Hox, V, et al.
(författare)
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Benefits and harm of systemic steroids for short- and long-term use in rhinitis and rhinosinusitis: an EAACI position paper
- 2020
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Ingår i: Clinical and translational allergy. - : Wiley. - 2045-7022. ; 10:1, s. 1-
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Tidskriftsartikel (refereegranskat)abstract
- Because of the inflammatory mechanisms of most chronic upper airway diseases such as rhinitis and chronic rhinosinusitis, systemic steroids have been used for their treatment for decades. However, it has been very well documented that—potentially severe—side-effects can occur with the accumulation of systemic steroid courses over the years. A consensus document summarizing the benefits of systemic steroids for each upper airway disease type, as well as highlighting the potential harms of this treatment is currently lacking. Therefore, a panel of international experts in the field of Rhinology reviewed the available literature with the aim of providing recommendations for the use of systemic steroids in treating upper airway disease.
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| 8. |
- Laniel, Dominique, et al.
(författare)
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Synthesis of Ultra‐Incompressible and Recoverable Carbon Nitrides Featuring CN4 Tetrahedra
- 2024
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Ingår i: Advanced Materials. - : WILEY-V C H VERLAG GMBH. - 0935-9648 .- 1521-4095. ; 36:3
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Tidskriftsartikel (refereegranskat)abstract
- Carbon nitrides featuring three-dimensional frameworks of CN4 tetrahedra are one of the great aspirations of materials science, expected to have a hardness greater than or comparable to diamond. After more than three decades of efforts to synthesize them, no unambiguous evidence of their existence has been delivered. Here, the high-pressure high-temperature synthesis of three carbon-nitrogen compounds, tI14-C3N4, hP126-C3N4, and tI24-CN2, in laser-heated diamond anvil cells, is reported. Their structures are solved and refined using synchrotron single-crystal X-ray diffraction. Physical properties investigations show that these strongly covalently bonded materials, ultra-incompressible and superhard, also possess high energy density, piezoelectric, and photoluminescence properties. The novel carbon nitrides are unique among high-pressure materials, as being produced above 100 GPa they are recoverable in air at ambient conditions.
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| 9. |
- Rudenko, A.N., et al.
(författare)
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Strong electron-phonon coupling and phonon-induced superconductivity in tetragonal C3N4 with hole doping
- 2024
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Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 109:1
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Tidskriftsartikel (refereegranskat)abstract
- C3N4 is a recently discovered phase of carbon nitrides with the tetragonal crystal structure [D. Laniel et al., Adv. Mater. (2023), doi:10.1002/adma.202308030] that is stable at ambient conditions. C3N4 is a semiconductor exhibiting flat-band anomalies in the valence band, suggesting the emergence of many-body instabilities upon hole doping. Here, using state-of-the-art first-principles calculations we show that hole-doped C3N4 reveals strong electron-phonon coupling, leading to the formation of a gapped superconducting state. The phase transition temperatures turn out to be strongly dependent on the hole concentration. We propose that holes could be injected into C3N4 via boron doping which induces, according to our results, a rigid shift of the Fermi energy without significant modification of the electronic structure. Based on the electron-phonon coupling and Coulomb pseudopotential calculated from first principles, we conclude that the boron concentration of 6 atoms per nm3 would be required to reach the critical temperature of ∼36 K at ambient pressure.
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