A5091419285- Laser-Matter Interactions and Applications
- Mass Spectrometry Techniques and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Spectroscopy and Quantum Chemical Studies
- Advanced X-ray Imaging Techniques
- Advanced Chemical Physics Studies
- ZnO doping and properties
- Quantum Mechanics and Non-Hermitian Physics
- Quantum chaos and dynamical systems
- Electrocatalysts for Energy Conversion
- Electron and X-Ray Spectroscopy Techniques
- Diamond and Carbon-based Materials Research
- Nuclear Physics and Applications
- Quantum, superfluid, helium dynamics
- Inorganic Fluorides and Related Compounds
- Advanced Electron Microscopy Techniques and Applications
- CO2 Reduction Techniques and Catalysts
- Molecular spectroscopy and chirality
- Ion-surface interactions and analysis
- Laser-Plasma Interactions and Diagnostics
- Quantum many-body systems
- Metalloenzymes and iron-sulfur proteins
- Quantum optics and atomic interactions
- Cold Atom Physics and Bose-Einstein Condensates
- Topological Materials and Phenomena
Technische Universität Dresden
2023-2024
Argonne National Laboratory
2015-2023
European X-Ray Free-Electron Laser
2023
Philipps University of Marburg
2009-2022
Southern Federal University
2016
Vrije Universiteit Amsterdam
2011-2013
Universitätsmedizin Rostock
1911
Here, we provide a detailed account of novel experiments employing electron-ion coincidence imaging to discriminate chiral molecules. The full three-dimensional angular scattering distribution electrons is measured after photoexcitation with either left or right circular polarized light. experiment performed using simplified photoelectron-photoion setup only single particle detector. Results are reported applying this technique enantiomers the molecule camphor three-photon ionization by...
X-ray transient absorption spectroscopy (X-TAS) has been used to study the light-induced hydrogen evolution reaction catalyzed by a tetradentate macrocyclic cobalt complex with formula [LCo(III)Cl2](+) (L = ligand), [Ru(bpy)3](2+) photosensitizer, and an equimolar mixture of sodium ascorbate/ascorbic acid electron donor in pure water. near edge structure (XANES) extended fine (EXAFS) analysis binary octahedral Co(III) precatalyst after illumination revealed situ formation Co(II) intermediate...
New capabilities at X-ray free-electron laser facilities allow the generation of two-colour femtosecond pulses, opening possibility performing ultrafast studies X-ray-induced phenomena. Particularly, experimental realization hetero-site-specific X-ray-pump/X-ray-probe spectroscopy is special interest, in which an pump pulse absorbed one site within a molecule and probe follows dynamics another same molecule. Here we show evidence hetero-site pump-probe signal. By using 10-fs are able to...
Simultaneous, enantiomer-specific identification of chiral molecules in multi-component mixtures is extremely challenging. Many established techniques for single-component analysis fail to provide selectivity and lack sensitivity dilute samples. Here we show how enantiomers may be differentiated by mass-selected photoelectron circular dichroism using an electron-ion coincidence imaging spectrometer. As proof concept, vapours containing ∼1% two monoterpene molecules, limonene camphor, are...
Abstract An accurate description of the interaction intense hard X-ray pulses with heavy atoms, which is crucial for many applications free-electron lasers, represents a hitherto unresolved challenge theory because enormous number electronic configurations and relativistic effects, need to be taken into account. Here we report results on multiple ionization xenon atoms by ultra-intense (about 10 19 W/cm 2 ) femtosecond at photon energies from 5.5 8.3 keV present theoretical model capable...
Here we report on a new simplified setup for velocity map photoelectron-photoion coincidence imaging using only single particle detector. We show that both photoelectrons and photoions can be extracted toward the same micro-channel-plate delay line detector by fast switching of high voltages ion optics. This retains essentially all features standard two-detector setup, viz., spatial resolution electron imaging, while slightly decreasing time-of-flight mass resolution. The paves way to...
The capability of generating two intense, femtosecond x-ray pulses with controlled time delay opens the possibility performing time-resolved experiments for induced phenomena. We have applied this to study photoinduced dynamics in diatomic molecules. In molecules composed low-Z elements, \textit{K}-shell ionization creates a core-hole state which main decay mode is an Auger process involving electrons valence shell. After decay, nuclear wavepackets transient two-valence-hole states continue...
We report the light-induced electronic and geometric changes taking place in "real time" of a multimolecular [Ru(bpy)3]2+/[Ni(PPh2NPh2)2(CH3CN)]2+/ascorbic acid photocatalytic system by time-resolved X-ray absorption spectroscopy (tr-XAS) nano- to microsecond time regime. Using tr-XAS allows us observe diffusion-governed electron transfer between excited photosensitizer nickel(II) proton reduction catalyst on nanosecond scale followed formation transient distorted tetrahedral Ni(I)...
Two methods of laser-induced mass-selective chiral analysis based on circular dichroism have been reported in the literature: photo-ion (PICD) and photo-electron (PECD). In PICD, a difference total ion yields upon multiphoton ionization with polarized light is measured, whereas PECD, observed angular distribution photoelectrons. Here, we report first coincident measurement PICD PECD effects. A home-built photoion-photoelectron coincidence spectrometer has used to measure both effects...
Characterization of the inner-shell decay processes in molecules containing heavy elements is key to understanding x-ray damage and materials for medical applications with Auger-electron-emitting radionuclides. The 1s hole states atoms can be produced by absorption tunable x rays resulting vacancy decays characterized recording emitted photons, electrons, ions. have large fluorescence yields that transfer intermediate electron shells then sequential Auger-electron transitions increase ion’s...
The evolution of charge carriers in photoexcited room temperature ZnO nanoparticles solution is investigated using ultrafast ultraviolet photoluminescence spectroscopy, Zn K-edge absorption and ab initio molecular dynamics (MD) simulations. excited at 4.66 eV, well above the band edge, shows that electron cooling conduction exciton formation occur <500 fs, excellent agreement with theoretical predictions. x-ray measurements, obtained upon excitation close to edge 3.49 are sensitive...
Herein, we review the current capabilities and potential of advanced single-particle imaging techniques to study photodynamics in isolated molecules. These reaction microscopes are able measure full three-dimensional energy angular distribution (correlated) particles such as electrons molecular fragments ejected after photoexcitation In particular, discuss performance a novel photoelectron-photoion coincidence spectrometer constructed at LaserLaB Amsterdam. This microscope was developed for...
Photoionization cross sections and partial ion yields of Xe XeF2 from 3d5/2, 3d3/2, F 1s subshells in the 660–740 eV range are compared to explore effects ligands. The 3d-ϵf continuum shape resonances dominate photoionization both atom molecule, but prominent appear section due nominal excitation 3d electrons lowest unoccupied molecular orbital (LUMO), a delocalized anti-bonding MO. Comparisons products molecule following show that charge-state distribution ions is shifted lower charge...
A versatile femtosecond ultraviolet (UV) pulse generation, a phase modulation, and characterization setup for coherent control applications are demonstrated.For high-performance of ultrashort pulses direct in the UV microelectromechanical-system-based 2D mirror array is applied.Multiple examples successful given, such as arbitrarily tailoring recompression open closed loop schemes.For simple effective generated pulses, autocorrelator based on two-photon absorption solar blind photomultiplier...
Detection of molecular chirality with high sensitivity and selectivity is important for many analytical practical applications. Photoionization has emerged as a very sensitive probe in molecules. We show here that table top setup femtosecond laser single imaging detector both photoelectrons photoions enables detection up to 3 orders magnitude better than the existing conventional absorption based techniques.
The $1s\phantom{\rule{4pt}{0ex}}\ensuremath{\rightarrow}\phantom{\rule{4pt}{0ex}}np$ Rydberg transitions below the $1s$ ionization thresholds of Kr and Xe are obscured in x-ray absorption spectra due to core-hole lifetime broadening. However, $np$ spectator electrons associated with those resonances can affect decay spectra. We report on ion charge-state distributions measured coincidence ${KL}_{2,3}$ ($K{\ensuremath{\alpha}}_{1,2}$), ${KM}_{2,3}$ ($K{\ensuremath{\beta}}_{1,3}$),...
The interaction of intense femtosecond x-ray pulses with molecules sensitively depends on the interplay between multiple photoabsorptions, Auger decay, charge rearrangement, and nuclear motion. Here, we report a combined experimental theoretical study ionization fragmentation iodomethane (CH3I) by ultraintense (∼1019 W/cm2) at 8.3 keV, demonstrating how these dynamics depend pulse energy duration. We show that timing steps leading to particular reaction product and, thus, product's final...
Here, we report the coincident measurement of PICD and PECD effects in 1-phenylethylamine upon multiphoton ionization. Both photo-ion circular dichroism (PICD) photo-electron (PECD) are methods to distinguish enantiomers. In PICD, a difference total ion yields ionization with polarized light is measured, whereas, PECD, observed angular distribution photoelectrons. on our continuous effort measure coincidence, i.e. simultaneously under same conditions using home-built photoion-photoelectron...
High-power Yb:InnoSlab lasers are proliferating into multiple modern application areas of laser physics ranging from plasma and nanolithography to driving optical parametric amplifiers for high-harmonic generation attosecond science. Here, we present, the layout, design first results an chirped-pulse amplifier system pumped by a kW-level average power Yb-InnoSlab laser. We describe layout concepts pump lasers, with particular attention specific principles required our application. In current...
In quantum materials, basic observables such as spectral functions and susceptibilities are determined by Green's their complex quasiparticle spectrum rather than bare electrons. Even in closed many-body systems, this makes a description terms of effective non-Hermitian (NH) Bloch Hamiltonians natural intuitive. Here, we discuss how the abundance stability nodal phases is drastically affected NH topology. While previous work has mostly considered degeneracies known exceptional points...
The control of multichannel ionic fragmentation dynamics in CF3I is studied by femtosecond pulse shaping and velocity map photoelectron photoion coincidence imaging. When photoexcited with laser pulses around 540 nm there are two major ions observed the time-of-flight mass spectrum, parent CF3I+ ion CF3+ fragment ion. In this first study we focussed on influence LCD-shaped molecular dynamics. three-dimensional recoil distribution electrons were imaged using a single delay line detector. By...
Non-Hermitian (NH) Hamiltonians have been shown to exhibit unique signatures, including the NH skin effect and an exponential spectral sensitivity with respect boundary conditions. Here, we investigate as what extent these remarkable phenomena, recently predicted observed in a broad range of settings, may also occur closed correlated fermionic systems that are governed by Hermitian many-body Hamiltonian. There, effectively quasiparticle description naturally arises Green's function formalism...
We have performed femtosecond X-ray spectroscopy measurements after UV photoexcitation of a colloidal solution ZnO nanoparticles. The results indicate sub-ps hole trapping at oxygen vacancies with shallowly-trapped electrons in the conduction band.