A5091646484- Ion-surface interactions and analysis
- Particle physics theoretical and experimental studies
- Particle Detector Development and Performance
- Integrated Circuits and Semiconductor Failure Analysis
- Dark Matter and Cosmic Phenomena
- Nuclear Physics and Applications
- Electron and X-Ray Spectroscopy Techniques
- Polymer Nanocomposite Synthesis and Irradiation
- Semiconductor materials and devices
- Nanopore and Nanochannel Transport Studies
- Astro and Planetary Science
- Laser-Matter Interactions and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Force Microscopy Techniques and Applications
- Spectroscopy and Quantum Chemical Studies
- Radiation Therapy and Dosimetry
- Neutrino Physics Research
- Laser-induced spectroscopy and plasma
- Radiation Effects in Electronics
- Silicon Carbide Semiconductor Technologies
- Laser Material Processing Techniques
- Electronic and Structural Properties of Oxides
- Glass properties and applications
- High-Energy Particle Collisions Research
- Nuclear materials and radiation effects
P.N. Lebedev Physical Institute of the Russian Academy of Sciences
2018-2024
National Research Nuclear University MEPhI
2015
Since a few breakthroughs in the fundamental understanding of effects swift heavy ions (SHI) decelerating electronic stopping regime matter have been achieved last decade, it motivated us to review state-of-the-art approaches modeling SHI effects. The track kinetics occurs via several well-separated stages: from attoseconds ion-impact ionization depositing energy target, femtoseconds electron transport and hole cascades, picoseconds lattice excitation response, nanoseconds atomic relaxation,...
We present a concurrent Monte Carlo (MC) - molecular dynamics (MD) approach to modeling of matter response excitation its electronic system. The two methods are combined on-the-fly at each time step in one code, TREKIS-4. MC model describes arrival irradiation, which the current implementation can consist photon, an electron, or fast ion. It also traces induced cascades secondary particles, electrons and holes, their energy exchange with atoms due scattering. excited atomic system is...
We present a multiscale model describing wet chemical etching of swift heavy ion tracks in olivine on the atomic scale. The approach combines Monte Carlo code TREKIS and molecular dynamics for simulations excitation structure transformations material after an impact. Analysis obtained positions proximity trajectory allows us to build up algorithm atom-by-atom removal from surface. describes primary highly damaged cylindrical track core followed by dissociation peripheral region formation...
Density functional–based molecular dynamics reveals a transient superionic state in Al 2 O 3 produced by nonthermal phase transition under extreme electronic excitation. At temperatures above T e ≈ 2.75 eV, the oxygen sublattice exhibits fluid behavior, whereas aluminum is solid state. This exists up to 3.25 where turns metallic–superionic; at 3.75 disorders. Quenching pressure >400 GPa freezes it into metastable mixed amorphous–crystalline subsystem disordered solid, one ordered.
The modern means of controlled irradiation by femtosecond lasers or swift heavy ion beams can transiently produce such energy densities in samples that reach collective electronic excitation levels the warm dense matter state, where potential interaction particles is comparable to their kinetic energies (temperatures a few eV). Such massive severely alters interatomic potentials, producing unusual nonequilibrium states and different chemistry. We employ density functional theory tight...
After ultrafast laser irradiation, a target enters poorly explored regime where physics of solid state overlaps with plasma and chemistry, creating an unusual synergy-a warm dense matter (WDM). We study theoretically the WDM kinetics chemistry in number group III-metal oxides highly excited electronic system. employ density functional theory to investigate possibility nonthermal transition materials into superionic under these conditions. Atomic properties are analyzed during transitions...
Abstract It is known that covalently bonded materials undergo nonthermal structure transformations upon ultrafast excitation of an electronic system, whereas metals exhibit phonon hardening in the bulk. Here we study how ionic bonds react to excitation. Density-functional molecular dynamics predicts crystals may melt nonthermally, however, into electronically insulating state, contrast covalent materials. We demonstrate band gap behavior during transitions depends on a bonding type: it...
We present a study of directional search for Dark Matter boosted forward when scattered by cosmic-ray nuclei, using module the NEWSdm experiment. The flux at edge Earth's atmosphere is expected to be pointing Galactic Center, with 15 20 times larger than in transverse direction. experiment consists 10 kg stack Nano Imaging Trackers, i.e.~newly developed nuclear emulsions AgBr crystal sizes down few tens nanometers. installed on an equatorial telescope. relatively long recoil tracks induced...
A standard Fricke dosimeter was used to measure the absorbed dose via oxidation yields of Fe3+ ions in an aqueous environment induced by soft X rays within "water window" spectral range. We also exploited property a neutral solution containing terephthalic acid as tool for selective detection OH radicals. Both dosimetric systems were irradiated using experimental pulsed laser-plasma X-ray source well conventional 1.25-MeV gamma rays. Radiation chemical and radicals determined be (5.13 ±...
At ambient conditions, SiC is known to be resistant irradiation with swift heavy ions (SHI) decelerating in the electronic stopping regime. However, there no experimental data on at elevated temperatures. To investigate this problem, we evaluate stability of SHI impacts high temperatures up 2200 K. We apply combination Monte-Carlo code TREKIS-3, describing excitation and atomic systems using temperature-dependent scattering cross-sections, molecular-dynamic modeling lattice response...
The velocity effect was studied in the synthesis of nanopores with a noncircular cross section by etching tracks swift heavy ions olivine. developed atomistic model for olivine irradiated predicts possibility synthesizing it. consists connected blocks that describe sequential stages track formation and etching. TREKIS Monte Carlo describes initial electronic lattice excitations nanoscale vicinity trajectory an incident ion. These results are used as conditions molecular dynamics simulation...
We present results of atomic-level simulations damage formation along the paths swift heavy ions (SHI) decelerated in electronic stopping regime amorphous polyethylene. The applied model combines Monte-Carlo code TREKIS-3, which describes excitation and atomic systems around ion trajectory, with molecular dynamics response system to excitation. simulation were used reconstruct configuration, shape size damaged region. demonstrated that positions maximum energy loss on trajectory do not...
We describe the formation of swift heavy ion tracks in polyethylene (PE) by combining Monte Carlo code TREKIS, which models electronic excitation nanometric proximity trajectory, with molecular dynamics simulating a response atomic system to perturbation. The model predicts circular amorphous PE but elliptical ones crystalline caused preferential propagation along polymer chains during cooling stage. obtained track sizes and shapes agree well high-resolution microscopy PE. velocity effect is...
We identified a mistake in script that caused erroneous absorbed doses calculated for different electronic temperatures. Table 1 shows corrected values. All other results and conclusions of the original paper are unaffected.
The modern means of controlled irradiation by femtosecond lasers or swift heavy ion beams can transiently produce such energy densities in samples that reach collective electronic excitation levels the warm dense matter state where potential interaction particles is comparable to their kinetic energies (temperatures a few eV). Such massive severely alters interatomic potentials, producing unusual nonequilibrium states and different chemistry. We employ density functional theory tight binding...