A5010663392- Atomic and Molecular Physics
- Advanced Chemical Physics Studies
- Laser-Matter Interactions and Applications
- Electron and X-Ray Spectroscopy Techniques
- Mass Spectrometry Techniques and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Laser-induced spectroscopy and plasma
- Advanced X-ray Imaging Techniques
- Spectroscopy and Quantum Chemical Studies
- Nuclear physics research studies
- Ion-surface interactions and analysis
- Advanced Electron Microscopy Techniques and Applications
- Nuclear Physics and Applications
- Crystallography and Radiation Phenomena
- Inorganic Fluorides and Related Compounds
- Laser-Plasma Interactions and Diagnostics
- Particle Accelerators and Free-Electron Lasers
- Cold Atom Physics and Bose-Einstein Condensates
- Photocathodes and Microchannel Plates
- Quantum optics and atomic interactions
- Atomic and Subatomic Physics Research
- Terahertz technology and applications
- Quantum, superfluid, helium dynamics
- Spectroscopy and Laser Applications
- High-pressure geophysics and materials
Donostia International Physics Center
2013-2024
European X-Ray Free-Electron Laser
2013-2024
Lomonosov Moscow State University
2013-2022
Moscow State University
1987-2021
Deutsches Elektronen-Synchrotron DESY
2013-2021
Ikerbasque
2020
Hamburg Centre for Ultrafast Imaging
2018
Max Planck Institute for the Structure and Dynamics of Matter
2018
Tohoku University
1996-2014
Universität Hamburg
1992-2012
The alignment of ions with an inner-shell vacancy resulting from ionisation by a fast charged particle is considered. has been calculated in the Born approximation using Herman-Skillman model. angular distribution and polarisation characteristic X-radiation Auger electrons decay aligned are discussed. It shown that theoretical anisotropy sensitive to wavefunctions used. results calculations much better agreement experiment than previous involving hydrogen-like functions.
For a number of atoms, systematic calculations have been made the alignment occurring in photoionisation inner subshells vicinity ionisation threshold. The influence centrifugal barrier effective partial potential on and anisotropy angular distribution polarisation X-rays Auger electrons is discussed. It shown that rather sensitive to models used.
General expressions for the angular distribution and polarization of photoelectrons in region autoionizing states have been obtained. It is shown that when an state has two or more channels decay a resonance structure can occur both polarization. For nsnp6mp Ne Ar, possible shapes energy dependence discussed. This sensitive to relation between matrix elements which characterize excitation through different channels.
Photoemission with a twist Attosecond time-resolved spectroscopy provides the ability to probe fastest electronic processes in atoms and solids. Yet photoemission process from solids is not fully understood. Siek et al. studied layered van der Waals material WSe 2 found that electron emission occurs as sequence of events are apparently time-ordered respect rising angular momentum involved initial states (see Perspective by Yakovlev Karpowicz). This result will help provide more detailed...
In single particle coherent x-ray diffraction imaging experiments, performed at free-electron lasers (XFELs), samples are exposed to intense pulses obtain single-shot patterns. The high intensity induces electronic dynamics on the femtosecond time scale in system, which can reduce contrast of obtained patterns and adds an isotropic background. We quantify degradation pattern from ultrafast damage by performing simulations a biological sample with different parameters. find that is...
Intense, circularly polarized extreme-ultraviolet and near-infrared (NIR) laser pulses are combined to double ionize atomic helium via the oriented intermediate He^{+}(3p) resonance state. Applying angle-resolved electron spectroscopy, we find a large photon helicity dependence of spectrum angular distribution electrons ejected from by NIR multiphoton absorption. The measured circular dichroism is unexpectedly found vary strongly as function intensity. experimental data well described...
The angular distribution and spin polarisation of Auger electrons following atomic collisions are discussed for the case where both target atom projectile unpolarised. General expressions in (LS)J coupling approximation obtained analysed. In particular p3/2 subshell vacancy anisotropy coefficient expressed terms Auger-decay matrix elements. It is shown that spin-polarised electron spectroscopy atoms can provide new information on process structure hole states, namely, elements their relative...
We present kinematically complete data on two-photon double ionization of Ne induced by short (∼25 fs) intense (∼5 × 1013 W cm−2) free-electron laser pulses at 44 eV. The observed electron energy spectrum points to the dominance 'sequential' ionization. analyse state-selective angular distributions as well two-electron correlation function, and suggest a method determine time delay between both steps. measured asymmetry (-) parameters significantly deviate from results an earlier...
A theoretical treatment is given of possible experiments on electron impact ionisation inner atomic shells, in which an inelastically scattered detected coincidence with the decay products ion formed, namely X-ray photon or Auger electron. General expressions for angular distribution and polarisation photons electrons are terms parameters describing anisotropy ionic state, statistical tensors depend scattering angle determined by mechanism. The tensors, asymmetry X-rays calculated 2p shell...
The angular anisotropy ${\mathrm{\ensuremath{\alpha}}}_{2}$ and spin polarization ${\ensuremath{\xi}}_{2}$ parameters have been calculated for Ar ${\mathit{L}}_{3}$MM, Kr ${\mathit{M}}_{4,5}$NN, Xe ${\mathit{N}}_{4,5}$OO, ${\mathit{M}}_{4,5}$NN Auger transitions using the multichannel multiconfiguration Dirac-Fock method (MMCDF). results of our MMCDF calculations are in good general agreement with experiment. We also determined separate contributions exchange, relaxation, channel interaction...
The angular distribution of photoelectrons produced by excitation polarized atoms to autoionizing states is analysed. In particular, core-excited in absorption synchrotron radiation laser-pumped excited are considered. A general expression for the arbitrarily oriented laser and beams obtained further reduced a simpler form particular geometry used experiments. case an isolated state (resonance) interacting with several continua considered parametrization observable parameters region...
Abstract The semiclassical approximation with rectilinear trajectory is used to calculate the impact‐parameter dependence of electronic stopping for fast‐proton collisions gas and solid atoms. effects arosen from electron shell rearrangement dynamic screening proton charge in a solid, on are studied case targets. calculation results compared experimental data approximate calculations based sum rules local density approximation.
Chirped Mo/Si multilayer coatings have been designed, fabricated, and characterized for use in extreme-ultraviolet attosecond experiments. By numerically simulating the reflection of pulse from a mirror during optimization procedure based on genetic algorithm, we obtain optimized layer designs. We show that normal incidence chirped mirrors capable reflecting pulses approximately 100 attoseconds (as) duration can be designed by enhancing reflectivity bandwidth optimizing phase-shift behavior....
A general expression for the angular correlation function of two emitted photoelectrons in sequential two-photon double ionization atoms is derived and discussed. The can be used analysis angle-resolved coincidence experiments. distributions electrons as measured non-coincidence experiments are also As an example, cross sections, functions Ne Ar have been calculated within MCHF MCDF approaches. results compared with recent performed at free-electron laser (FLASH) facility.
The alignment of ions with an inner-shell vacancy resulting from ion-atom collisions is considered. calculations are made in the Born approximation for a number atoms and subshells using hydrogen-like, screened hydrogen-like Herman-Skillman models. It shown that complicated function incoming ion velocity large low-velocity region. Comparison experimental data results electron impact ionisation.
Spectra and angular distributions of photoelectrons from ionization atoms by a combination two short pulses in the XUV IR range are theoretically considered. The transition streaking regime for ultrashort to sideband formation longer is discussed. For sufficiently high energy (a few hundreds eV), peculiarity distribution gross structure sidebands investigated.
Two-color (x-ray+infrared) electron spectroscopy is used for investigating laser-assisted KLL Auger decay following 1s photoionization of atomic Ne with few-femtosecond x-ray pulses from the Linac Coherent Light Source. In an angle-resolved experiment, overall width laser-modified Auger-electron spectrum and its structure change significantly as a function emission angle. The spectra are characterized by strong intensity variation sidebands revealing gross structure. This caused, predicted...
The angular distribution of Auger electrons in the decay resonantly excited atomic states is studied theoretically. two-step model used for a description process with electron as spectator. Expressions anisotropy parameters jK and jj coupling schemes are obtained excitation closed-shell system. A close relation between anisotropies resonant normal processes found within framework spectator model. Numerical calculations transitions Ar, Kr Xe presented compared recent experiments.
The angular distribution and spin polarisation of Auger electrons free atoms are discussed. In the (LS) J-coupling approximation anisotropy coefficient expressed in terms Auger-decay matrix elements particular case d3/2 d5/2 subshell vacancies. For some transitions Ar, Kr Xe have been calculated. Herman-Skillman atomic model was used to calculate amplitudes. all cases considered is small (less than 20%). However, large its measurement may be useful for studying process.
It has recently been demonstrated that apart from the electron detection realized in attosecond streak camera, also ion can be used for establishing extreme-ultraviolet pump/visible probe experiments, temporally resolving dynamics of atomic inner-shell relaxation processes. We utilize this method studying Auger decay krypton atoms following creation vacancy states 3d shell. is shown electronic occurs through different pathways, each involving cascades sequential steps which are followed...