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165 results on '"Kočišek, Jaroslav"'

1. Condensed Matter Systems Exposed to Radiation: Multiscale Theory, Simulations, and Experiment

Author

Solov'yov, Andrey V., Verkhovtsev, Alexey V., Mason, Nigel J., Amos, Richard A., Bald, Ilko, Baldacchino, Gérard, Dromey, Brendan, Falk, Martin, Fedor, Juraj, Gerhards, Luca, Hausmann, Michael, Hildenbrand, Georg, Hrabovský, Miloš, Kadlec, Stanislav, Kočišek, Jaroslav, Lépine, Franck, Ming, Siyi, Nisbet, Andrew, Ricketts, Kate, Sala, Leo, Schlathölter, Thomas, Wheatley, Andrew, and Solov'yov, Ilia A.

Subjects
Physics - Chemical Physics, Condensed Matter - Mesoscale and Nanoscale Physics, Physics - Atomic Physics, Physics - Biological Physics, Physics - Plasma Physics
Abstract

This paper reviews the new highly interdisciplinary research field studying the behavior of condensed matter systems exposed to radiation. The paper highlights several relevant examples of recent advances in the field and provides a roadmap for the development of the field in the next decade. Condensed matter systems exposed to radiation may have very different natures, being inorganic, organic or biological, finite or infinite, be composed of many different molecular species or materials, existing in different phases (solid, liquid, gaseous or plasma) and operating under different thermodynamic conditions. The essential and novel element of this research is that, despite the vast diversity of such systems, many of the key phenomena related to the behavior of irradiated systems (such as radiation-induced damage, mechanisms of damage repair and control, radiation protection, etc.) are very similar and can be understood based on the same fundamental theoretical principles and computational approaches. One of the essential features of the aforementioned phenomena concerns their multiscale nature as the manifestation of the radiation-induced effects occurring at different spatial and temporal scales ranging from the atomic to the macroscopic. The multiscale nature of the effects and similarity of their manifestation in systems of different origins necessarily brings together different disciplines, such as physics, chemistry, biology, materials and nano-science, and biomedical research, demonstrating numerous interlinks and commonalities between them. This research field is highly relevant to many novel and emerging technologies and medical applications., Comment: Roadmap paper; 376 pages, 32 figures. Submitted to Chemical Reviews

Published
2023
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2. Solvation of Silver Ions in Noble Gases He, Ne, Ar, Kr, and Xe

Author

Mahmoodi-Darian, Masoomeh, Martini, Paul, Tiefenthaler, Lukas, Kočišek, Jaroslav, Scheier, Paul, and Echt, Olof

Subjects
Physics - Atomic and Molecular Clusters
Abstract

We use a novel technique to solvate silver cations in small clusters of noble gases. The technique involves formation of large, superfluid helium nanodroplets that are subsequently electron ionized, mass-selected by deflection in an electric field, and doped with silver atoms and noble gases (Ng) in pickup cells. Excess helium is then stripped from the doped nanodroplets by multiple collisions with helium gas at room temperature, producing cluster ions that contain no more than a few dozen noble gas atoms and just a few (or no) silver atoms. Under gentle stripping conditions helium atoms remain attached to the cluster ions, demonstrating their low vibrational temperature. Under harsher stripping conditions some of the heavier noble gas atoms will be evaporated as well, thus enriching stable clusters Ng$_n$Ag$_m^+$ at the expense of less stable ones. This results in local anomalies in the cluster ion abundance which is measured in a high-resolution time-of-flight mass spectrometer. Based on these data we identify specific "magic" sizes n of particularly stable ions. There is no evidence though for enhanced stability of Ng$_2$Ag$^+$, in contrast to the high stability of Ng$_2$Au$^+$ that derives from the covalent nature of the bond for heavy noble gases. "Magic" sizes are also identified for Ag$_2^+$ dimer ions complexed with He or Kr. Structural models will be tentatively proposed. A sequence of magic numbers $n$ = 12, 32, 44, indicative of three concentric solvation shells of icosahedral symmetry, is observed for He$_n$H$_2$O$^+$.

Published
2022
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3. Dissociative Electron Attachment Dynamics of a Promising Cancer Drug Indicates Its Radiosensitizing Potential.

Author

Izadi, Farhad, Luxford, Thomas F. M., Sedmidubská, Barbora, Arthur‐Baidoo, Eugene, Kočišek, Jaroslav, Ončák, Milan, and Denifl, Stephan

Subjects
ELECTRON gas, GAS phase reactions, CONDENSED matter, ELECTRONS, ANTINEOPLASTIC agents
Abstract

2‐Bromo‐1‐(3,3‐dinitroazetidin‐1‐yl)ethan‐1‐one (RRx‐001) is a hypoxic cell chemotherapeutics with already demonstrated synergism in combined chemo‐radiation therapy. The interaction of the compound with secondary low‐energy electrons formed in large amounts during the physico‐chemical phase of the irradiation may lead to these synergistic effects. The present study focuses on the first step of RRx‐001 interaction with low‐energy electrons in which a transient anion is formed and fragmented. Combination of two experiments allows us to disentangle the decay of the RRx‐001 anion on different timescales. Sole presence of the electron initiates rapid dissociation of NO2 and HNO2 neutrals while NO2− and Br− anions are produced both directly and via intermediate complexes. Based on our quantum chemical calculations, we propose that bidirectional state switching between π*(NO2) and σ*(C−Br) states explains the experimental spectra. The fast dynamics monitored will impact the condensed phase chemistry of the anion as well. [ABSTRACT FROM AUTHOR]

Published
2024
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4. Dissoziative Elektronenanlagerungsdynamik eines vielversprechenden Krebsmedikaments zeigt sein Potential als Radiosensitizer.

Author

Izadi, Farhad, Luxford, Thomas F. M., Sedmidubská, Barbora, Arthur‐Baidoo, Eugene, Kočišek, Jaroslav, Ončák, Milan, and Denifl, Stephan

Abstract

Copyright of Angewandte Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2024
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5. Condensed Matter Systems Exposed to Radiation: Multiscale Theory, Simulations, and Experiment

Author

Solov’yov, Andrey V., primary, Verkhovtsev, Alexey V., additional, Mason, Nigel J., additional, Amos, Richard A., additional, Bald, Ilko, additional, Baldacchino, Gérard, additional, Dromey, Brendan, additional, Falk, Martin, additional, Fedor, Juraj, additional, Gerhards, Luca, additional, Hausmann, Michael, additional, Hildenbrand, Georg, additional, Hrabovský, Miloš, additional, Kadlec, Stanislav, additional, Kočišek, Jaroslav, additional, Lépine, Franck, additional, Ming, Siyi, additional, Nisbet, Andrew, additional, Ricketts, Kate, additional, Sala, Leo, additional, Schlathölter, Thomas, additional, Wheatley, Andrew E. H., additional, and Solov’yov, Ilia A., additional

Published
2024
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10. Roadmap on dynamics of molecules and clusters in the gas phase

Author

Zettergren, Henning, Domaracka, Alicja, Schlathölter, Thomas, Bolognesi, Paola, Díaz-Tendero, Sergio, Łabuda, Marta, Tosic, Sanja, Maclot, Sylvain, Johnsson, Per, Steber, Amanda, Tikhonov, Denis, Castrovilli, Mattea Carmen, Avaldi, Lorenzo, Bari, Sadia, Milosavljević, Aleksandar R., Palacios, Alicia, Faraji, Shirin, Piekarski, Dariusz G., Rousseau, Patrick, Ascenzi, Daniela, Romanzin, Claire, Erdmann, Ewa, Alcamí, Manuel, Kopyra, Janina, Limão-Vieira, Paulo, Kočišek, Jaroslav, Fedor, Juraj, Albertini, Simon, Gatchell, Michael, Cederquist, Henrik, Schmidt, Henning T., Gruber, Elisabeth, Andersen, Lars H., Heber, Oded, Toker, Yoni, Hansen, Klavs, Noble, Jennifer A., Jouvet, Christophe, Kjær, Christina, Nielsen, Steen Brøndsted, Carrascosa, Eduardo, Bull, James, Candian, Alessandra, and Petrignani, Annemieke

Published
2021
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15. Interaction of low-energy electrons with radiosensitizers.

Author

Sedmidubská, Barbora and Kočišek, Jaroslav

Abstract

We provide an experimentalist's perspective on the present state-of-the-art in the studies of low-energy electron interactions with common radiosensitizers, including compounds used in combined chemo-radiation therapy and their model systems. Low-energy electrons are important secondary species formed during the interaction of ionizing radiation with matter. Their role in the radiation chemistry of living organisms has become an important topic for more than 20 years. With the increasing number of works and reviews in the field, we would like to focus here on a very narrow area of compounds that have been shown to have radio-sensitizing properties on the one hand, and high reactivity towards low-energy electrons on the other hand. Gas phase experiments studying electron attachment to isolated molecules and environmental effects on reaction dynamics are reviewed for modified DNA components, nitroimidazoles, and organometallics. In the end, we provide a perspective on the future directions that may be important for transferring the fundamental knowledge about the processes induced by low-energy electrons into practice in the field of rational design of agents for concomitant chemo-radiation therapy. [ABSTRACT FROM AUTHOR]

Published
2024
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22. Interaction of 4-nitrothiophenol with low energy electrons: Implications for plasmon mediated reactions.

Author

Schürmann, Robin, Luxford, Thomas F. M., Vinklárek, Ivo S., Kočišek, Jaroslav, Zawadzki, Mateusz, and Bald, Ilko

Subjects
SINGLE electron transfer mechanisms, ELECTRONS, PLASMONS (Physics), FREE electron lasers, METAL nanoparticles, CHARGE exchange, PRECIOUS metals
Abstract

The reduction of 4-nitrothiophenol (NTP) to 4-4′-dimercaptoazobenzene (DMAB) on laser illuminated noble metal nanoparticles is one of the most widely studied plasmon mediated reactions. The reaction is most likely triggered by a transfer of low energy electrons from the nanoparticle to the adsorbed molecules. Besides the formation of DMAB, dissociative side reactions of NTP have also been observed. Here, we present a crossed electron-molecular beam study of free electron attachment to isolated NTP in the gas-phase. Negative ion yields are recorded as a function of the electron energy, which helps to assess the accessibility of single electron reduction pathways after photon induced electron transfer from nanoparticles. The dominant process observed with isolated NTP is associative electron attachment leading to the formation of the parent anion of NTP. Dissociative electron attachment pathways could be revealed with much lower intensities, leading mainly to the loss of functional groups. The energy gained by one electron reduction of NTP may also enhance the desorption of NTP from nanoparticles. Our supporting experiments with small clusters, then, show that further reaction steps are necessary after electron attachment to produce DMAB on the surfaces. [ABSTRACT FROM AUTHOR]

Published
2020
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29. Interaction of 4-nitrothiophenol with low energy electrons

Author

Schürmann, Robin Mathis (Dr.), Luxford, Thomas, Vinklárek, Ivo, Kočišek, Jaroslav, Zawadzki, Mateusz, and Balko, Ilko

Subjects
viruses, ddc:540, Institut für Chemie
Abstract

The reduction of 4-nitrothiophenol (NTP) to 4-4′-dimercaptoazobenzene (DMAB) on laser illuminated noble metal nanoparticles is one of the most widely studied plasmon mediated reactions. The reaction is most likely triggered by a transfer of low energy electrons from the nanoparticle to the adsorbed molecules. Besides the formation of DMAB, dissociative side reactions of NTP have also been observed. Here, we present a crossed electron-molecular beam study of free electron attachment to isolated NTP in the gas-phase. Negative ion yields are recorded as a function of the electron energy, which helps to assess the accessibility of single electron reduction pathways after photon induced electron transfer from nanoparticles. The dominant process observed with isolated NTP is associative electron attachment leading to the formation of the parent anion of NTP. Dissociative electron attachment pathways could be revealed with much lower intensities, leading mainly to the loss of functional groups. The energy gained by one electron reduction of NTP may also enhance the desorption of NTP from nanoparticles. Our supporting experiments with small clusters, then, show that further reaction steps are necessary after electron attachment to produce DMAB on the surfaces.

Published
2020

38. Ion and radical chemistry in (H2O2)N clusters

Author

Pysanenko, Andriy, primary, Pluhařová, Eva, additional, Vinklárek, Ivo S., additional, Rakovský, Jozef, additional, Poterya, Viktoriya, additional, Kočišek, Jaroslav, additional, and Fárník, Michal, additional

Published
2020
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39. Electron-triggered chemistry in HNO3/H2O complexes† †Electronic supplementary information (ESI) available: Mass spectrum from electron ionization of H2O/HNO3 complexes, benchmark calculations, and the calculated cluster structures. See DOI: 10.1039/c7cp01205e Click here for additional data file

Author

Lengyel, Jozef, Ončák, Milan, Fedor, Juraj, Kočišek, Jaroslav, Pysanenko, Andriy, Beyer, Martin K., and Fárník, Michal

Subjects
Chemistry
Abstract

Electron attachment to mixed HNO3/H2O clusters yields several atmospherically relevant species such as NO3 –, HONO and OH radical., Polar stratospheric clouds, which consist mainly of nitric acid containing ice particles, play a pivotal role in stratospheric chemistry. We investigate mixed nitric acid–water clusters (HNO3)m(H2O)n, m ≈ 1–6, n ≈ 1–15, in a laboratory molecular beam experiment using electron attachment and mass spectrometry and interpret our experiments using DFT calculations. The reactions are triggered by the attachment of free electrons (0–14 eV) which leads to subsequent intracluster ion–molecule reactions. In these reactions, the nitrate anion NO3 – turns out to play the central role. This contradicts the electron attachment to the gas-phase HNO3 molecule, which leads almost exclusively to NO2 –. The nitrate containing clusters are formed through at least three different reaction pathways and represent terminal product ions in the reaction cascade initiated by the electron attachment. Besides, the complex reaction pathways represent a new hitherto unrecognized source of atmospherically important OH and HONO molecules.

Published
2017

42. Decomposition of Iron Pentacarbonyl Induced by Singly and Multiply Charged Ions and Implications for Focused Ion Beam-Induced Deposition

Author

Indrajith, Suvasthika, primary, Rousseau, Patrick, additional, Huber, Bernd A., additional, Nicolafrancesco, Chiara, additional, Domaracka, Alicja, additional, Grygoryeva, Kateryna, additional, Nag, Pamir, additional, Sedmidubská, Barbora, additional, Fedor, Juraj, additional, and Kočišek, Jaroslav, additional

Published
2019
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44. Ion and radical chemistry in (H2O2)N clusters.

Author

Pysanenko, Andriy, Pluhařová, Eva, Vinklárek, Ivo S., Rakovský, Jozef, Poterya, Viktoriya, Kočišek, Jaroslav, and Fárník, Michal

Abstract

We investigate the ionization induced chemistry of hydrogen peroxide in (H2O2)N clusters generated after the pickup of individual H2O2 molecules on large free ArM, M¯ ≈ 160, nanoparticles in molecular beams. Positive and negative ion mass spectra are recorded after an electron ionization of the clusters at energies 5–70 eV and after a slow electron attachment (below 4 eV), respectively. The spectra demonstrate that (H2O2)N clusters with N ≥ 20 are formed on argon nanoparticles. This is the first experimental report on hydrogen peroxide clusters in molecular beams. The major negative cluster ion series (H2O2)nO2− indicates O2− ion formation. The dissociative electron attachment to H2O2 molecules in the gas phase yielded only OH− and O− (Nandi et al., Chem. Phys. Lett., 2003, 373, 454). These ions and the series containing them are much less abundant in the clusters. We propose a sequence of ion–molecule and radical reactions to explain the formation of O2−, HO2− and other ions observed in the negatively charged cluster ion series. Since hydrogen peroxide plays an important role in many areas of chemistry from the Earth's atmosphere to biological tissues, our study opens new horizons for experimental investigations of hydrogen peroxide chemistry in complex environments. [ABSTRACT FROM AUTHOR]

Published
2020
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49. Electron Attachment to Microhydrated Deoxycytidine Monophosphate

Author

Kočišek, Jaroslav, Sedmidubská, Barbora, Indrajith, Suvasthika, Fárník, Michal, and Fedor, Juraj

Abstract

DNA constituents are effectively decomposed via dissociative electron attachment (DEA). However, the DEA contribution to radiation damage in living tissues is a subject of ongoing discussion. We address an essential question, how aqueous environment influences the DEA to DNA. In particular, we report experimental fragmentation patterns for DEA to microhydrated 2-deoxycytidine 5-monophosphate (dCMP). Isolated dCMP was previously set as a model to describe mechanisms of DNA-strand breaks induced by secondary electrons and decomposes primarily by dissociation of the C–O phosphoester bond. We show that hydrated molecules decompose via dissociation of the C–N glycosidic bond followed by dissociation of the P–O bond. This significant change of the proposed mechanism can be interpreted by a reactive role of water in the postattachment dynamics. Comparison of the fragmentation with previous macroscopic irradiation studies suggests that the actual contribution of DEA to DNA radiation damage in living tissue is rather small.

Published
2024
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