A5076279607- Advanced Chemical Physics Studies
- Atomic and Molecular Physics
- Laser-Matter Interactions and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Mass Spectrometry Techniques and Applications
- Advanced X-ray Imaging Techniques
- Electron and X-Ray Spectroscopy Techniques
- Spectroscopy and Quantum Chemical Studies
- Advanced Electron Microscopy Techniques and Applications
- Photochemistry and Electron Transfer Studies
- Particle Accelerators and Free-Electron Lasers
- Ion-surface interactions and analysis
- Spectroscopy and Laser Applications
- Molecular Junctions and Nanostructures
- Inorganic Fluorides and Related Compounds
- Atmospheric Ozone and Climate
- Laser-Plasma Interactions and Diagnostics
- Quantum, superfluid, helium dynamics
- Cold Atom Physics and Bose-Einstein Condensates
- Catalytic Processes in Materials Science
- Nuclear Physics and Applications
- Crystallography and Radiation Phenomena
- Atmospheric chemistry and aerosols
- Photocathodes and Microchannel Plates
- Analytical Chemistry and Sensors
University of Gothenburg
2016-2025
Origo (Iceland)
2022
Uppsala University
2007-2016
University of Oxford
2004-2014
Tohoku University
2006-2014
Stockholm University
2011-2014
Institute for Molecular Science
2014
Sophia University
2007
MAX IV Laboratory
1999
Lund University
1999
Resetting the clock on photoemission The ability to produce attosecond pulses of light provides access some fastest electronic processes occurring within atoms. Tracking temporal dynamics process in which an atom absorbs a high-energy photon and electron escapes has exposed discrepancy between initial experimental findings subsequent theoretical modeling. Isinger et al. present ultrafast that can account for distinguish different contributions neon reveal “electron shake-up” may explain...
Abstract Rabi oscillations are periodic modulations of populations in two-level systems interacting with a time-varying field 1 . They ubiquitous physics applications different areas such as photonics 2 , nano-electronics 3 electron microscopy 4 and quantum information 5 While the theory developed by was intended for fermions gyrating magnetic fields, Autler Townes realized that it could also be used to describe coherent light–matter interactions within rotating-wave approximation 6 Although...
A quantitative determination of 2s vacancy lifetimes in surface and bulk atoms free Ne clusters has been made. While for the inner-valence hole a ps lifetime, it reduces to 6+/-1 fs cluster atoms. For atoms, lifetime is on average longer than 30 fs. The estimate was obtained from fits high-resolution photoelectron spectra clusters. shortening attributed coordination dependent interatomic Coulombic decay, which extremely sensitive internuclear distances.
Theory predicts that double-core-hole (DCH) spectroscopy can provide a new powerful means of differentiating between similar chemical systems with sensitivity not hitherto possible. Although DCH ionization on single site in molecules was recently measured double- and single-photon absorption, double-core holes vacancies two different sites, allowing unambiguous analysis, have remained elusive. Here we report direct observation sites produced via sequential two-photon using short, intense...
Organic chromophores with heteroatoms possess an important excited state relaxation channel from optically allowed {\pi}{\pi}* to a dark n{\pi}*state. We exploit the element and site specificity of soft x-ray absorption spectroscopy selectively follow electronic change during {\pi}{\pi}*/n{\pi}* internal conversion. As hole forms in n orbital conversion, near edge fine structure (NEXAFS) spectrum at heteroatom K-edge exhibits additional resonance. demonstrate concept nucleobase thymine,...
We have investigated multiphoton multiple ionization dynamics of xenon atoms using a new x-ray free-electron laser facility, SPring-8 Angstrom Compact free electron LAser (SACLA) in Japan, and identified that Xen+ with n up to 26 is produced at photon energy 5.5 keV. The observed high charge states (n≥24) are via five-photon absorption, evidencing the occurrence absorption involving deep inner shells. A newly developed theoretical model, which shows good agreement experiment, elucidates...
We have performed x-ray two-photon photoelectron spectroscopy using the Linac Coherent Light Source free-electron laser in order to study double core-hole (DCH) states of CO2, N2O, and N2. The experiment verifies theory behind chemical sensitivity two-site DCH by comparing a set small molecules with respect energy shift state extracting relevant parameters from this shift.
Abstract The recent development of ultrafast extreme ultraviolet (XUV) coherent light sources bears great potential for a better understanding the structure and dynamics matter. Promising routes are advanced control nonlinear spectroscopy schemes in XUV energy range, yielding unprecedented spatial temporal resolution. However, their implementation has been hampered by experimental challenge generating pulse sequences with precisely controlled timing phase properties. In particular, direct...
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...
Shape resonances in physics and chemistry arise from the spatial confinement of a particle by potential barrier. In molecular photoionization, these barriers prevent electron escaping instantaneously, so that nuclei may move modify potential, thereby affecting ionization process. By using an attosecond two-color interferometric approach combination with high spectral resolution, we have captured changes induced nuclear motion on centrifugal barrier sustains well-known shape resonance...
Abstract The conversion of photon energy into other energetic forms in molecules is accompanied by charge moving on ultrafast timescales. We directly observe the motion at a specific site an electronically excited molecule using time-resolved x-ray photoelectron spectroscopy (TR-XPS). extend concept static chemical shift from conventional XPS excited-state (ESCS), which connected to framework potential model. This allows us invert TR-XPS spectra dynamic atom. demonstrate power sulphur 2 p...
Abstract The light-induced ultrafast switching between molecular isomers norbornadiene and quadricyclane can reversibly store release a substantial amount of chemical energy. Prior work observed signatures dynamics in both upon ultraviolet excitation but could not follow the electronic relaxation all way back to ground state experimentally. Here we study after exciting (201 nanometres) using time-resolved gas-phase extreme photoelectron spectroscopy combined with non-adiabatic simulations....
Quantum entanglement between the degrees of freedom encountered in classical world is challenging to observe due surrounding environment. To elucidate this issue, we investigate generated over ultrafast timescales a bipartite quantum system comprising two massive particles: free-moving photoelectron, which expands mesoscopic length scale, and light-dressed atomic ion, represents hybrid state light matter. Although photoelectron spectra are measured classically, allows us reveal information...
A magnetic bottle spectrometer of the type recently developed by Eland et al. [Phys. Rev. Lett. 90, 053003 (2003).] has been implemented for use with synchrotron radiation, allowing multidimensional electron spectroscopy. Its application to Xe $4d$ double Auger decay reveals all energy pathways involved. The dominant path is a cascade process rapid (6 fs) ejection first followed slower ($>23\text{ }\text{ }\mathrm{fs}$) emission second electron. Weaker processes implying 3 are also...
Energies of the hollow molecules ${\mathrm{CH}}_{4}^{2+}$ and ${\mathrm{NH}}_{3}^{2+}$ with double vacancies in $1s$ shells have been measured using an efficient coincidence technique combined synchrotron radiation. The energies these states determined accurately by high level electronic structure calculations can be well understood on basis a simple theoretical model. Their major decay pathway, successive Auger emissions, leads first to new form triply charged ion core hole two valence...
When exposed to ultraintense x-radiation sources such as free electron lasers (FELs) the innermost electronic shell can efficiently be emptied, creating a transient hollow atom or molecule. Understanding femtosecond dynamics of systems is fundamental achieving atomic resolution in flash diffraction imaging noncrystallized complex biological samples. We demonstrate capacity correlation method called "partial covariance mapping" probe neon atoms intense 8 fs pulses 1062 eV photons. A complete...
Abstract The first steps in photochemical processes, such as photosynthesis or animal vision, involve changes electronic and geometric structure on extremely short time scales. Time-resolved photoelectron spectroscopy is a natural way to measure changes, but has been hindered hitherto by limitations of available pulsed light sources the vacuum-ultraviolet soft X-ray spectral region, which have insufficient resolution energy simultaneously. unique combination intensity, resolution,...
FERMI is a novel class of free-electron laser that capable producing femtosecond pulses ultraviolet and x-ray light, essential to studying ultrafast processes in matter. A new investigation characterizes FERMI's pulse shape confirms it routinely generates Gaussian lasting few tens femtoseconds.
Abstract Using electron spectroscopy, we have investigated nanoplasma formation from noble gas clusters exposed to high-intensity hard-x-ray pulses at ~5 keV. Our experiment was carried out the SPring-8 Angstrom Compact free LAser (SACLA) facility in Japan. Dedicated theoretical simulations were performed with molecular dynamics tool XMDYN. We found that this unprecedented wavelength regime is a highly indirect process. In argon investigated, mainly formed through secondary cascading...