A. De Fanis
A5067748892- Advanced Chemical Physics Studies
- Atomic and Molecular Physics
- X-ray Spectroscopy and Fluorescence Analysis
- Advanced X-ray Imaging Techniques
- Mass Spectrometry Techniques and Applications
- Electron and X-Ray Spectroscopy Techniques
- Laser-Matter Interactions and Applications
- Spectroscopy and Laser Applications
- Spectroscopy and Quantum Chemical Studies
- Photochemistry and Electron Transfer Studies
- Particle Accelerators and Free-Electron Lasers
- Advanced Electron Microscopy Techniques and Applications
- Atmospheric Ozone and Climate
- Photocathodes and Microchannel Plates
- Inorganic Fluorides and Related Compounds
- Ion-surface interactions and analysis
- Advanced X-ray and CT Imaging
- Laser-Plasma Interactions and Diagnostics
- Medical Imaging Techniques and Applications
- Quantum, superfluid, helium dynamics
- Catalytic Processes in Materials Science
- Crystallography and Radiation Phenomena
- Laser-induced spectroscopy and plasma
- Cold Atom Physics and Bose-Einstein Condensates
- Atomic and Subatomic Physics Research
European X-Ray Free-Electron Laser
2014-2025
Diamond Light Source
2011-2016
University of Manchester
2013
Japan Synchrotron Radiation Research Institute
2003-2010
Shimadzu (United Kingdom)
2010
Tohoku University
2000-2008
Sophia University
2004-2008
SPring-8
2003-2007
University of Southampton
1998-2001
Istituto Nazionale per la Fisica della Materia
1998
Abstract Following structural dynamics in real time is a fundamental goal towards better understanding of chemical reactions. Recording snapshots individual molecules with ultrashort exposure times key ingredient this goal, as atoms move on femtosecond (10 −15 s) timescales. For condensed-phase samples, ultrafast, atomically resolved structure determination has been demonstrated using X-ray and electron diffraction. Pioneering experiments have also started addressing gaseous samples....
Abstract The Diamond beamline I13 for imaging and coherence applications is dedicated to hard X‐ray on the micro nano‐lengthscale. Two independent stations will be operated in a separate building at distance of 250 m from source. branch perform in‐line phase contrast tomography over large field view 6–35 keV energy range. In addition it possible switch full‐field microscopy with 50 nm spatial resolution. Other microscopies developed according scientific needs. Resolution beyond limitations...
The FERMI facility in Trieste, Italy, is ideal for generating and measuring light characterized by tunable polarization states the vacuum ultraviolet spectral range. New results reveal a high degree of (>0.9) over 26--55 nanometers.
Ultrashort x-ray pulses from free-electron lasers can efficiently charge up and trigger the full fragmentation of molecules. By coincident detection to five ions resulting rapid Coulomb explosion highly charged iodomethane, we show that three-dimensional equilibrium geometry this prototypical polyatomic system be determined measured ion momenta with help a buildup model. Supported by simulations how would reflect specific changes in molecular bond lengths angles, demonstrate...
A central motivation for the development of x-ray free-electron lasers has been prospect time-resolved single-molecule imaging with atomic resolution. Here, we show that photoelectron diffraction—where a emitted after absorption illuminates molecular structure from within—can be used to image increase internuclear distance during x-ray-induced fragmentation an O2 molecule. By measuring molecular-frame emission patterns two-photon sequential K-shell ionization in coincidence fragment ions,...
Finding the lowest energy configuration of N unit charges on a sphere, known as Thomson's problem, is long-standing query which has only been studied via numerical simulations. We present its physical realization using multiply charged He nanodroplets. The charge positions are determined by x-ray coherent diffractive imaging with Xe contrast agent. In neutral droplets, filaments resulting from atoms condensing quantum vortices observed. Unique to however, clusters that condense distributed...
The nonlinear interaction of x rays with matter is at the heart understanding and controlling ultrafast molecular dynamics from an atom-specific viewpoint, providing new scientific analytical opportunities to explore structure small quantum systems. At increasingly high x-ray intensity, sensitivity ultrashort pulses specific electronic states emerging short-lived transient intermediates particular relevance for our fundamental multiphoton absorption processes. In this work, intense...
The I13 beamline of Diamond Light Source has been operational since December 2011. encompass two fully independent branches devoted to coherent imaging experiments (coherent x-ray diffraction, diffraction and ptychography) (in-line phase contrast imaging, tomography full-field microscopy). This paper gives an overview the current status experimental stations on both outlines planned developments.
Abstract Short wavelength free-electron lasers (FELs), providing pulses of ultrahigh photon intensity, have revolutionized spectroscopy on ionic targets. Their exceptional flux enables multiple absorptions within a single femtosecond pulse, which in turn allows for deep insights into the photoionization process itself as well evolving states target. Here we employ ultraintense from FEL FERMI to spectroscopically investigate sequential emission electrons gaseous, atomic argon neutral ground...
The ultrafast structural dynamics of water following inner-shell ionization is a crucial issue in high-energy radiation chemistry. We have exposed isolated molecules to short x-ray pulse from free-electron laser and detected momenta all produced ions coincidence. By combining experimental results theoretical modeling, we can image dissociation individual unprecedented detail. reveal significant molecular H2O2+, such as asymmetric deformation bond-angle opening, leading two-body or three-body...
We report on a multiparticle coincidence experiment performed at the European X-ray Free-Electron Laser Small Quantum Systems instrument using COLTRIMS reaction microscope. By measuring two ions and electrons in coincidence, we investigate double core-hole generation O_{2} molecules gas phase. Single-site two-site core holes have been identified their molecular-frame electron angular distributions obtained for breakup of oxygen molecule into doubly charged ions. The measured are compared to...
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...
Ultrafast X-ray spectroscopies require flexible properties together with high temporal and spectral resolution. Here, we demonstrate simultaneous sub-20 fs sub-eV resolutions for pump/probe experiments, without the need additional photon arrival-time monitors.
We have measured the angular distribution of carbon K-Auger electrons from fixed in space, core-ionized, CO molecules coincidence with kinetic energy release C+ and O+ fragments. find a very narrow ejection Auger direction oxygen an oscillatory diffraction pattern. Even for similar electron energies, strongly depends on symmetry final state.
Intense x-ray pulses provide the first investigation of fleeting electronic structure a neon atom right after it has absorbed an photon, setting stage for future studies transient states matter.
The photochemically induced ring-opening isomerization reaction of 1,3-cyclohexadiene to 1,3,5-hexatriene is a textbook example pericyclic and has been amply investigated with advanced spectroscopic techniques. main open question the identification single reactive state which drives process. generally accepted description pathway starts valence excitation lowest lying bright state, followed by passage through conical intersection doubly excited finally branching between either return ground...
Excited double-core-hole states of isolated water molecules resulting from the sequential absorption two x-ray photons have been investigated. These are formed through an alternative pathway, where initial step core ionization is accompanied by shake-up a valence electron, leading to same final as in core-ionization followed core-excitation pathway. The capability free-electron laser deliver very intense, short, and tunable light pulses fully exploited identify different pathways.Received 16...
The Small Quantum Systems instrument is one of the six operating instruments European XFEL, dedicated to atomic, molecular and cluster physics communities. started its user operation at end 2018 after a commissioning phase. design characterization beam transport system are described here. X-ray optical components beamline detailed, performances, transmission focusing capabilities reported. It shown that can be effectively focused as predicted by ray-tracing simulations. impact non-ideal...
Measurements of photoelectron angular distributions for carbon K-shell ionization fixed-in-space CO2 molecules with the molecular axis oriented along, perpendicular and at 45° to electric vector light are reported. The major features these measured spectra fairly well reproduced by calculations employing a relaxed-core Hartree–Fock approach. In contrast distribution N2, which exhibits rich structure dominated f-wave (l = 3) shape resonance, photoionization is quite unstructured over entire...
Fragmentation of the SF6 molecule upon F 1s excitation has been studied by resonant photoemission. The atomiclike Auger line exhibits characteristic Doppler profile that depends on direction photoelectron momentum relative to polarization vector radiation as well photon energy. measured profiles are analyzed model simulation takes account anisotropy emission in molecular frame. extracted from data decreases with an increase F-SF5 internuclear distance.
The resonant Auger spectrum from the decay of F 1s-excited CF4 is measured. Several lines exhibit a nondispersive kinetic energy as exciting photon tuned through resonance region. 1s(-1) atomiclike line split into two components due to emission electrons by fragment in motion, when electron observed along polarization vector light. This Doppler splitting direct evidence that core excitation leads T(d)-->C(3v) symmetry lowering, elongation specific C-F bond preferentially aligned incident photon.
We have carried out angle-resolved measurement for the C $1s$ photoelectron shakeup satellites of gaseous CO molecules, at unprecedented energy resolution, and resolved vibrational structures one $^{2}\ensuremath{\Sigma}^{+}$ two $^{2}\ensuremath{\Pi}$ bands. The present ab initio calculations potential curves these satellite states relevant Franck-Condon analysis well reproduce bands confirm assignments.
Ultrafast dissociation of the SF6 molecule following F 1s → a*1g excitation has been studied by coincident measurement kinetic energy resonantly emitted electron and momentum fragment ion. The nuclear motion takes place on same time scale as Auger decay, leading to atomic-like (1s)-Auger lines in spectrum. De-tuning from resonance changes ratio two scales involved. We measured shift line parameters that describe corresponding ionic fragmentation dynamics a function detuning energy. Our data...
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...