A5066332340- X-ray Spectroscopy and Fluorescence Analysis
- Advanced Chemical Physics Studies
- Crystallography and Radiation Phenomena
- Electron and X-Ray Spectroscopy Techniques
- Advanced X-ray Imaging Techniques
- Atomic and Molecular Physics
- Rare-earth and actinide compounds
- Spectroscopy and Quantum Chemical Studies
- Diamond and Carbon-based Materials Research
- Boron and Carbon Nanomaterials Research
- Magnetic and transport properties of perovskites and related materials
- Quantum, superfluid, helium dynamics
- Advanced Condensed Matter Physics
- High-pressure geophysics and materials
- Fullerene Chemistry and Applications
- Laser-Matter Interactions and Applications
- Semiconductor materials and devices
- Metal and Thin Film Mechanics
- Medical Imaging Techniques and Applications
- Magnetic properties of thin films
- Polymer Nanocomposite Synthesis and Irradiation
- Advanced Electron Microscopy Techniques and Applications
- Physics of Superconductivity and Magnetism
- Particle Accelerators and Free-Electron Lasers
- Electron Spin Resonance Studies
MAX IV Laboratory
2014-2025
Lund University
2014-2025
Uppsala University
1998-2016
Skåne University Hospital
2016
Getinge (Sweden)
2016
Monash University
2000
We use x-ray emission spectroscopy to examine the influence of intermolecular interaction on local electronic structure liquid water. By comparing spectra water molecule and water, we find a strong involvement a(1)-symmetry valence-orbital in hydrogen bonding. The molecules, where one bond is broken at site, separately determined. Our results provide an illustration important potential for elucidating basic features liquids.
Free-electron lasers providing ultra-short high-brightness pulses of X-ray radiation have great potential for a wide impact on science, and are critical element unravelling the structural dynamics matter. To fully harness this potential, we must accurately know properties: intensity, spectrum temporal profile. Owing to inherent fluctuations in free-electron lasers, mandates full characterization properties each every pulse. While diagnostics these exist, they often invasive many cannot...
We present resonant x-ray Raman scattering results on ${\mathrm{Sr}}_{2}{\mathrm{CuO}}_{2}{\mathrm{Cl}}_{2}$, a model compound for high- ${T}_{c}$ superconductors. demonstrate that the $\mathrm{dd}$ excitations can be observed and show polarization dependence used to identify excitations. find transition from ${d}_{{x}^{2}{\ensuremath{-}y}^{2}}$ ground state ${d}_{\mathrm{xy}}$ excited at 1.35 eV degenerate ${d}_{\mathrm{xz}}$ ${d}_{\mathrm{yz}}$ states 1.7 eV. From analysis of we conclude...
Observations made in oxygen K emission of C${\mathrm{O}}_{2}$ show that the symmetry selective character resonant x-ray is excitation energy dependent. Electronically dipole forbidden O lines are observed for at $1s\ensuremath{\rightarrow}{\ensuremath{\pi}}^{*}$ resonance, and they gradually reduced upon detuning below threshold. The occurrence transitions explained terms dynamical breaking due to vibronic coupling, observation quenching as an effective this coupling. Scattering theory...
Soft x-ray absorption (SXAS) and emission (SXES) spectroscopies were applied to study the nitrogen bonding structure in magnetron sputtered CNx thin films. By comparing with calculated spectra of N different model systems, three main environments can be identified: (i) C≡N bonds, a sharp SXAS peak at 399.5 eV, (ii) pyridine-like (i.e., bonded two C atoms), an resonance ∼398.5 (iii) substituted graphite, possibly one sp3 carbon as neighbor (SXAS energy ∼401 eV). These bondings are present all...
Fluorinated amorphous carbon (a-CFx) films were studied by high-resolution x-ray absorption, emission, and photoelectron spectroscopy. The composition local bonding information obtained correlated with substrate temperature during deposition. data suggest that the structure of a-CFx is mostly rings connected CF2 groups. cross linking increases temperature.
SPECIES is an undulator-based soft X-ray beamline that replaced the old I511 at MAX II storage ring. aimed high-resolution ambient-pressure photoelectron spectroscopy (APXPS), near-edge absorption fine-structure (NEXAFS), emission (XES) and resonant inelastic scattering (RIXS) experiments. The has two branches use a common elliptically polarizing undulator monochromator. beam switched between by changing focusing optics after Both have separate exit slits, refocusing dedicated permanent...
A new experimental technique uses an x-ray free-electron laser to reveal charge dynamics within a molecule following removal of electron, paving the way for broader understanding molecular transfer.
The SPECIES beamline has been transferred to the new 1.5 GeV storage ring at MAX IV Laboratory. Several improvements have made and its endstations during transfer. Together Ambient Pressure X-ray Photoelectron Spectroscopy Resonant Inelastic Scattering are capable of conducting photoelectron spectroscopy in elevated pressure regimes with enhanced time-resolution flux scattering experiments improved resolution flux. Both offer a unique capability for low photon energies vacuum ultraviolet...
The O $K\ensuremath{\alpha}$ x-ray emission spectra of water clusters with different sizes and conformations embedded in a continuum medium are simulated. calculations have successfully explained the experimental both gas liquid phases. It is shown that very sensitive to local hydrogen bonding structures. Strong electron sharing between molecules observed its possible connection covalency discussed. experimentally strong excitation energy dependence has been interpreted terms polarization...
Abstract Thermally driven chemistry as well materials’ functionality are determined by the potential energy surface of a systems electronic ground state. This makes central and powerful concept in physics, materials science. However, direct experimental access to locally around atomic centers its long-range structure lacking. Here we demonstrate how sub-natural linewidth resonant inelastic soft x-ray scattering at vibrational resolution is utilized determine state surfaces detect changes...
The fluorescence yield spectrum of the double excitations in helium has been measured. All three Rydberg series converging to $N\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}2$ threshold are resolved, and intensity individual lines is determined. variation through each indicates that radiative decay channel cannot be neglected when discussing helium. This calls for a revision interpretation absorption spectrum, sets limit using ion method monitor probability.
Nonlinear x-ray spectroscopy The extension of nonlinear optics to the spectral domain is a promising direction in development spectroscopy. Although theoretical concepts were developed decades ago, scientists still struggle implement them because elusive nature effects. Eichmann et al. now present atomic momentum (AMS), which based on detection scattered atom after transfer from photons (see Perspective by Pfeifer). authors show how AMS can observe stimulated Raman scattering signals at neon...
Resonant inelastic x-ray scattering (RIXS) is a major method for investigation of electronic structure and dynamics, with applications ranging from basic atomic physics to materials science. In RIXS applied inversion-symmetric systems, it has generally been accepted that strict parity selectivity applies in the sub–kilo–electron volt region. contrast, we show selection rule violated spectra free homonuclear diatomic O 2 molecule. By analyzing spectral dependence on angle, demonstrate...
Seeded free electron lasers theoretically have the intensity, tunability, and resolution required for multiphoton spectroscopy of atomic molecular species. Using seeded laser FERMI a novel detection scheme, we revealed two-photon excitation spectra dipole-forbidden doubly excited states in helium. The spectral profiles lowest $(\ensuremath{-}1,0{)}^{+1}$ $^{1}{S}^{e}$ $(0,1{)}^{0}$ $^{1}{D}^{e}$ resonances display energy shifts meV range that depend on pulse intensity. results are explained...
With the invention of femtosecond X-ray free-electron lasers (XFELs), studies light-induced chemical reaction dynamics and structural reach a new era, allowing for time-resolved diffraction spectroscopy. To ultimately probe coherent electron nuclear on their natural time length scales, nonlinear spectroscopy schemes have been proposed. In this contribution, we want to critically assess experimental realisation at current-day XFEL sources, by presenting first attempts demonstrate stimulated...
The dynamics of chemical reactions in solution are paramount importance fields ranging from biology to materials science. Because the hydrogen-bond network and proton govern behavior aqueous solutions, they have been subject numerous studies over years. Here, we report observation a previously unknown associative state hydroxide ion that forms when neighboring water molecule approaches ion, utilizing resonant inelastic soft X-ray scattering (RIXS) quantum dynamical simulations....
A recent experimental study [J.-E. Rubensson et al., Phys. Rev. Lett. 83, 947 (1999)] measured a significant fluorescence yield of the He( ${2lnl}^{\ensuremath{'}}$) photoexcited resonances, showing major qualitative differences from nonrelativistic predictions. We present further theoretical these states, and perform $R$-matrix multichannel quantum defect theory calculations to extract ionization cross sections. These results are in excellent agreement with newer, higher-resolution...
X-ray-emission threshold-electron coincidence spectroscopy has been applied to ${\mathrm{N}}_{2}$, ${\mathrm{O}}_{2}$, and ${\mathrm{N}}_{2}\mathrm{O}$. The main features of the spectra can be interpreted as conventional core level threshold electron spectra, free from postcollision interaction effects. relative cross sections for adiabatic ionization close-lying hole states vibrational substates are presented. results compared theoretical predictions state-of-the-art photoelectron discussed...
The spin transition in LaCoO3 is investigated by temperature-dependent resonant soft X-ray emission spectroscopy near the Co 2p absorption edges. This element-specific technique more bulk sensitive with respect to temperature induced spin-state of Co3+ ions than other high-energy spectroscopic methods. interpreted and discussed ab-initio density-functional theory within fixed-spin moment method, which found yield consistent spectral functions experimental data. changes for as a function...
We present a detailed experimental-theoretical analysis of O $K$-edge resonant $1\ensuremath{\sigma}\ensuremath{-}2\ensuremath{\pi}$ inelastic x-ray scattering (RIXS) from carbon monoxide with unprecedented energy resolution. employ high-level ab initio calculations to compute the potential curves states involved in RIXS process and simulate measured spectra using wave-packet-propagation formalism, including Coulomb coupling final-state manifold. The theoretical allows us explain all key...