A5103120018- Advanced Chemical Physics Studies
- Atomic and Molecular Physics
- Mass Spectrometry Techniques and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Electron and X-Ray Spectroscopy Techniques
- Laser-Matter Interactions and Applications
- Spectroscopy and Quantum Chemical Studies
- Spectroscopy and Laser Applications
- Advanced X-ray Imaging Techniques
- Photochemistry and Electron Transfer Studies
- Ion-surface interactions and analysis
- Laser-Plasma Interactions and Diagnostics
- Atmospheric Ozone and Climate
- Inorganic Fluorides and Related Compounds
- Photocathodes and Microchannel Plates
- Laser-induced spectroscopy and plasma
- Advanced Electron Microscopy Techniques and Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Particle Accelerators and Free-Electron Lasers
- Molecular Junctions and Nanostructures
- Nuclear physics research studies
- Atomic and Subatomic Physics Research
- Nuclear Physics and Applications
- Radioactive element chemistry and processing
- Quantum, superfluid, helium dynamics
Tohoku University
2015-2025
ShanghaiTech University
2025
Nihon University
2023
SPring-8
2013-2021
Sendai University
2017-2019
Synchrotron soleil
2019
University of Turku
2019
University of Tartu
2019
Graduate School USA
2015
Advanced Institute of Materials Science
2007-2015
Ionization and fragmentation of methylselenol (CH(3)SeH) molecules by intense (>10(17) W/cm(2)) 5 fs x-ray pulses (ħω=2 keV) are studied coincident ion momentum spectroscopy. We contrast the measured charge state distribution with data on atomic Kr, determine kinetic energies resulting ionic fragments, compare them to outcome a Coulomb explosion model. find signatures ultrafast redistribution from inner-shell ionized Se atom its molecular partners, observe significant displacement...
Abstract We describe an experimental method to probe the adsorption of water at surface isolated, substrate-free TiO 2 nanoparticles (NPs) based on soft X-ray spectroscopy in gas phase using synchrotron radiation. To understand interfacial properties between and surface, a shell was adsorbed NPs. used two different ways control hydration level NPs: first scheme, initially solvated NPs were dried second one, dry generated thanks commercial aerosol generator exposed vapor. XPS identify...
Interatomic Coulombic decay (ICD) from an Auger-final dicationic state is observed in the Ar dimer. A $2p$ inner-shell vacancy created by photoionization replaced with $3s$ and $3p$ vacancies via intra-atomic Auger decay. The subject to ICD which one of electrons same atom fills while neighboring emitted as electron. This process unambiguously identified electron-ion-ion coincidence spectroscopy kinetic energy electron release between ${\mathrm{Ar}}^{+}$ ${\mathrm{Ar}}^{2+}$ are measured coincidence.
Carbon 1s photoelectron spectra of methane are measured over a photon energy range between 480 eV and 1200 eV. Additional components appear the individual symmetric stretching vibrational attributed to excitations asymmetric bending vibrations due recoil high-energy emission. This effect is evidence for violation Franck-Condon principle which states that neither positions nor momenta nuclei change during ionization event.
This article reviews the current status of inner-shell spectroscopies free atoms and molecules using high-resolution soft-x-ray monochromators installed in beamlines at third-generation synchrotron radiation facilities. Beamlines endstations devoted to atomic molecular various types experimental techniques, such as ion yield spectroscopy, resonant photoemission spectroscopy multiple-coincidence momentum imaging, are described. Experimental results for K-shell excitation Ne, O H2O CO2, C...
We explore the potential of double core hole electron spectroscopy for chemical analysis in terms x-ray two-photon photoelectron spectroscopy. The creation deep single and vacancies induces significant reorganization valence electrons. corresponding relaxation energies interatomic are evaluated by complete active space self-consistent field (CASSCF) calculations. propose a method on how to experimentally extract these quantities measurement ionization potentials (IPs) (DIPs). influence...
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...
The concept, design and performance of Japan's compact free-electron laser (FEL) facilities, the SPring-8 Compact SASE Source test accelerator (SCSS) Angstrom free electron LAser (SACLA), their applications in mainly atomic, molecular optical science are reviewed. At SCSS, intense, ultrafast FEL pulses at extreme ultraviolet (EUV) wavelengths have been utilized for investigating various multi-photon processes atoms, molecules clusters by means ion spectroscopy. quantum effect...
Ultrafast electron transfer in dissociating iodomethane and fluoromethane molecules was studied at the Linac Coherent Light Source free-electron laser using an ultraviolet-pump, X-ray-probe scheme. The results for both are discussed with respect to nature of their UV excitation different chemical properties. Signatures long-distance intramolecular charge observed species, a quantitative analysis its distance dependence is carried out states up I21+. reconstructed critical distances good...
The core-level photoelectron spectra of N2 molecules are observed at high energy resolution, resolving the 1σg and 1σu components as well vibrational in extended region from threshold up to 1 keV. σg/σu cross section ratios display modulation a function momentum due two-centre interference, analogous classical Young’s double-slit experiment, predicted by Cohen Fano long time ago. Cohen–Fano interference modulations different phases depending on excitations core-ionized state. Extensive ab...
We report the first observation of electron-transfer-mediated decay (ETMD) and interatomic Coulombic (ICD) from triply charged states with an inner-valence vacancy, using Ar dimer as example. These ETMD ICD processes, which lead to fragmentation Ar(3+)-Ar into Ar(2+)-Ar(2+) Ar(3+)-Ar+, respectively, are unambiguously identified by electron-ion-ion coincidence spectroscopy in kinetic energy or electron release between two fragment ions measured coincidence.
We have investigated multiple ionization of Xe clusters by 61-nm 1011–1012 W/cm2 extreme-ultraviolet light pulses at the free-electron laser facility, SPring-8 Compact SASE Source test accelerator, in Japan, using a dead-time-free three-dimensional momentum spectrometer. It was found that average kinetic energy atomic Xe+ ions increases when increasing power density and cluster size. For these experimental conditions significant frustration photoionization occurs but no indication for...
The sequential inner-shell multiple ionization of krypton was investigated at the Linac Coherent Light Source using ion time-of-flight spectroscopy photon energies above (2 keV) and below (1.5 $L$ edge with two x-ray pulse lengths (5 80 fs, nominally) various energies. At 2.5 mJ energy, charge states up to Kr${}^{17+}$ were recorded for $M$-shell Kr${}^{21+}$ $L$-shell ionization. Comparing experimental state distribution Monte Carlo rate-equation calculations, we find a strong enhancement...
Second-order autocorrelation spectra of XUV free-electron laser pulses from the Spring-8 Compact SASE Source (SCSS) have been recorded by time and momentum resolved detection two-photon single ionization He at 20.45 eV using a split-mirror delay-stage in combination with high-resolution recoil-ion spectroscopy (COLTRIMS). From trace we extract coherence 8 ± 2 fs mean pulse duration 28 5 fs, much shorter than estimations based on electron bunch-length measurements. Simulations within partial...
A brief account of the developments in photodissociation studies free molecules by VUV and soft x-ray sources is given as an extended introduction. Then two typical experimental setups are described for multiple-ion coincidence momentum imaging high-resolution Auger electron–ion imaging. Finally, some individual cases molecular dissociation following core-hole creation examined, to illustrate how complex multidimensional data produced can be represented interpreted. The new techniques based...
We used cold target recoil ion momentum spectroscopy for a comprehensive study of the decay neon dimer $({\mathrm{Ne}}_{2})$ after removal $1s$ electron from one atoms dimer. Multiple pathways are found and identified, mostly being connected to different types interatomic Coulombic (ICD) such as ``direct'' ICD which happens via transfer virtual photon, ``exchange'' an mediated decay. A quantitative theoretical analysis these processes can be in preceding paper by Demekhin et al. [Phys. Rev....
We have measured the vibrational structures of N 1s photoelectron mainline and satellites gaseous N2 molecule with resolution better than 75 meV. The gerade ungerade symmetries core-ionized (mainline) states are resolved energetically, symmetry-dependent angular distributions for satellite emission allow us to resolve Sigma Pi shake-up (satellite) states. Symmetry-adapted cluster-expansion configuration-interaction calculations potential energy curves along a Franck-Condon analysis well...
The carbon 1s photoelectron spectrum of CF4 measured at photon energies from 330to1500eV shows significant contributions nonsymmetric vibrational modes. These increase linearly as the energy increases. excitation these modes, which is not predicted in usual Franck–Condon point view, arises recoil momentum imparted to atom ionization process. A theory presented for quantitative prediction effect; predictions this are agreement measurements. experiments also yield frequencies symmetric and...
The first experimental evidence of rotational Doppler broadening in photoelectron spectra, reported here, show good agreement with recently described theoretical predictions. dependence the on temperature and kinetic energy is quantitatively predicted by theory. experiments verify that contributions to linewidth are comparable those from translational must be considered analysis high-resolution spectra. A classical model accounting for this newly observed effect presented.