A5067406349- Advanced Chemical Physics Studies
- Mass Spectrometry Techniques and Applications
- Atomic and Molecular Physics
- Ion-surface interactions and analysis
- Spectroscopy and Quantum Chemical Studies
- Atmospheric Ozone and Climate
- Photochemistry and Electron Transfer Studies
- Atmospheric chemistry and aerosols
- DNA and Nucleic Acid Chemistry
- Quantum, superfluid, helium dynamics
- Advanced biosensing and bioanalysis techniques
- Inorganic Fluorides and Related Compounds
- RNA Interference and Gene Delivery
- Molecular Junctions and Nanostructures
- Electron and X-Ray Spectroscopy Techniques
- nanoparticles nucleation surface interactions
- Molecular Spectroscopy and Structure
- Astrophysics and Star Formation Studies
- Radiation Therapy and Dosimetry
- Chemical Reactions and Isotopes
- Photocathodes and Microchannel Plates
- Muon and positron interactions and applications
- Atomic and Subatomic Physics Research
- Electron Spin Resonance Studies
- Plasma Diagnostics and Applications
Czech Academy of Sciences, J. Heyrovský Institute of Physical Chemistry
2016-2025
Czech Academy of Sciences
2014-2021
Universität Innsbruck
2019
Normandie Université
2016-2017
Université de Caen Normandie
2015-2017
École Nationale Supérieure d'Ingénieurs de Caen
2015-2017
Gdańsk University of Technology
2017
Centre de Recherche sur les Ions, les Matériaux et la Photonique
2015-2016
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2015
Centre National de la Recherche Scientifique
2015
While matter is irradiated with highly-energetic particles, it may become chemically modified. Thereby, the reactions of free low-energy electrons (LEEs) formed as secondary particles play an important role. It unknown to what degree and by which mechanism LEEs contribute action electron-affinic radiosensitisers applied in radiotherapy hypoxic tumours. Here we show that effectively cause reduction radiosensitiser nimorazole via associative electron attachment cross-section exceeding most...
In this perspective, we review experiments with molecules picked up on clusters in molecular beams the focus processes atmospheric and interstellar chemistry.
Abstract This roadmap article highlights recent advances, challenges and future prospects in studies of the dynamics molecules clusters gas phase. It comprises nineteen contributions by scientists with leading expertise complementary experimental theoretical techniques to probe on timescales spanning twenty order magnitudes, from attoseconds minutes beyond, for systems ranging complexity smallest (diatomic) nanoparticles. Combining some these opens up new avenues unravel hitherto unexplored...
We review the progress in low-energy electron collisions with molecular systems relevant to developing new chemo-radiotherapies and provide an experimentalist's perspective of field.
The interest in the electron impact-induced ligand release from MeCpPtMe3 [trimethyl(methylcyclopentadienyl)platinum(IV)] is motivated by its widespread use as a precursor focused and ion beam nanofabrication. By experimentally studying impact dissociative ionization of under single-collision conditions, we have found that removal two methyl radicals energetically more favorable than one radical even comparable to nondissociative MeCpPtMe3. This observation explained structural rearrangement...
Abstract We studied free electron collision-induced fragmentation of HFO1234ze(E) (C3H2F4). The motivation
of the present study is to assess possibility using this gas in resistive plate chamber
detectors and for interest its electron-induced decomposition. Two electron-collision setups,
which complement each other, are used. Additionally, interpretation data supported
by quantum chemical calculations. provide absolute partial cross sections both...
Pure acetylene and mixed Ar-acetylene clusters are formed in supersonic expansions of acetylene/argon mixtures analysed using reflectron time-of-flight mass spectrometer with variable electron energy ionization source. Acetylene composed more than a hundred molecules generated at the concentration ≈8%, while species produced low concentrations (≈0.7%). The dependence spectra revealed process mechanisms clusters. above threshold for molecule 11.5 eV results main ionic fragment progression...
Mixed (HNO3)m(H2O)n clusters generated in supersonic expansion of nitric acid vapor are investigated two different experiments, (1) time-of-flight mass spectrometry after electron ionization and (2) Na doping photoionization. This combination complementary methods reveals that only containing at least one molecule generated, is, the serves as nucleation center expansion. The experiments also suggest four water molecules needed for HNO3 acidic dissociation. undoubtedly proved by ionization;...
Uptake of several atmospheric molecules on free ice nanoparticles was investigated. Typical examples were chosen: water, methane, NO(x) species (NO, NO(2)), hydrogen halides (HCl, HBr), and volatile organic compounds (CH(3)OH, CH(3)CH(2)OH). The cross sections for pickup these (H(2)O)(N) with the mean size N≈260 (diameter ~2.3 nm) measured in a molecular beam experiment. These determined from cluster velocity decrease due to momentum transfer during process. For water dynamics simulations...
We report a dramatic difference in electron-induced decomposition of aggregates iron pentacarbonyl [Fe(CO)5] when compared to its isolated form. The are deposited on free argon nanoparticles (clusters) with the mean size several hundreds atoms and interact an electron beam 0–25 eV energy. negatively charged products analyzed mass-spectroscopically. These various Fe/CO composition always desorb from cluster surface; no mixed anion–Ar fragments detected. While anions containing one atom show...
We report cross sections for pickup of guest molecules on neutral argon and water clusters with the mean sizes in range from N¯=50 to 600. The experiments are supported by molecular dynamics simulations analytical models based interaction potentials. consistent their assumed spherical shape follow approximately theoretically justified N1/3 dependence. On other hand, depart this dependence considerably larger starting N¯≥300. interpret increase section occurrence highly irregular shapes...
In a combined experimental and theoretical study we characterize dissociative electron attachment (DEA) to, electronically excited states of, Fe(CO)5. Both are relevant for electron-induced degradation of The strongest DEA channel is cleavage one metal-ligand bond that leads to production Fe(CO)4-. High-resolution spectra Fe(CO)4- reveal fine structures at the onset vibrational excitation channels. Effective range R-matrix theory successfully reproduces these as well dramatic rise cross...
The fragmentation of uracil molecules and pure nano-hydrated clusters by <sup>12</sup>C<sup>4+</sup> ion impact is investigated.
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 DNA. In particular, we report experimental fragmentation patterns for microhydrated 2-deoxycytidine 5-monophosphate (dCMP). Isolated dCMP was previously set as model describe mechanisms DNA-strand breaks induced by secondary electrons...
Biocompatible DNA origami nanostructures (DONs) attract significant interest as potential targeted drug carriers. Their sensitivity to various environmental triggers is beneficial a release or decomposition mechanism, but it also hinders their stability; therefore, they require some extent of cross-linking. Using cisplatin, we demonstrate that molecule can both act therapeutic and cross-linking agent for DONs. In this work, triangular two-dimensional DONs are loaded with ∼1000 cisplatin...
We investigate the electron ionization of clusters generated in mixed Ar-water expansions. The energy dependent ion yields reveal neutral cluster composition and structure: water fully covered with Ar solvation shell are formed under certain expansion conditions. argon atoms shield embedded (H2O)n resulting threshold above ≈15 eV for all fragments. also mediate more complex reactions clusters: e.g., charge transfer between Ar(+) occurs threshold; at higher energies ~28 eV, an excitonic...
Experiment and theory are combined to study the interaction of low energy electrons with microhydrated uracil its halogenated analogues 5-fluorouracil 5-bromouracil. We report electron ionization (EI) attachment (EA) mass spectra for uracils different degrees hydration. Both EI EA lead evaporation water molecules. The number evaporated molecules serves as a measure transferred solvent. Upon EI, amount neighboring is similar all three studied species. On other hand, upon rises significantly...
In a combined experimental and theoretical study, we probe the dissociative electron attachment in isocyanic acid HNCO. The absolute cross section for NCO^{-} fragment shows sharp onset fine structures near threshold. autoionizing state responsible is found both R-matrix calculation using analytic continuation coupling constant. involved A^{'} resonance has mixed π^{*}/σ^{*} character along dissociating bond thus combines effects of nonzero angular momentum dipole-supported states. This...
We experimentally show that N–H bond cleavage in the pyrrole molecule following resonant electron attachment is allowed and controlled by motion of atoms which are not dissociating, namely, carbon-attached hydrogen atoms. use this fact to steer efficiency cleavage. In order interpret experimental findings, we have developed a method for locating all virtual states an electron-molecule system complex plane, based on all-electron R-matrix scattering calculations. Mapping these as function...
The formation of negative ions following electron impact to ethanol (CH3CH2OH) and trifluoroethanol (CF3CH2OH) is studied in the gas phase by means a crossed electron–molecular beam experiment condensed via Electron Stimulated Desorption (ESD) fragment from corresponding molecular films under UHV conditions. Gas exhibits two pronounced resonances, located at 5.5 eV 8.2 eV, associated with remarkable selectivity decomposition precursor ion. While low energy resonance exclusively decomposes...