Publications by authors named "Yuhiro Sato"
Crystallization is a fundamental natural phenomenon and the ubiquitous physical process in materials science for the design of new materials. So far, experimental observations of the structural dynamics in crystallization have been mostly restricted to slow dynamics. We present here an exclusive way to explore the dynamics of crystallization in highly controlled conditions (i.
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- Characterizing nanoparticle uniformity is essential because crystalline defects impact their unique properties, which are important for scientific and technological applications.!* -
- Recent advancements in X-ray free-electron lasers (XFELs) allow for high-resolution structural analysis of nanoparticles, but reconstructing 3D structures from single-shot diffraction patterns is challenging due to random particle orientation.!* -
- This report presents a new analysis method that uses wide-angle X-ray scattering (WAXS) to effectively identify defects in nanoparticles, demonstrated through experiments on xenon clusters which revealed angular correlations in the diffraction patterns and provided insights into structural information and stacking faults.!*
Article Synopsis
- The study focuses on improving methods to reconstruct the structure of nanoscale samples using coherent diffractive imaging with X-ray free-electron lasers, even when the quality of the diffraction data is low.
- A new refinement method is introduced that uses a gradient search technique, which takes into account gaps in the diffraction patterns and limited photon detection, enhancing convergence by starting with an initial structure estimate.
- The method was successfully applied to experimental data from an Xe cluster at the SACLA facility, demonstrating effective reconstruction of electron density from challenging diffraction patterns, thereby aiding in the analysis of samples with low scattering power.
Femtosecond laser pulses have opened new frontiers for the study of ultrafast phase transitions and nonequilibrium states of matter. In this Letter, we report on structural dynamics in atomic clusters pumped with intense near-infrared (NIR) pulses into a nanoplasma state. Employing wide-angle scattering with intense femtosecond x-ray pulses from a free-electron laser source, we find that highly excited xenon nanoparticles retain their crystalline bulk structure and density in the inner core long after the driving NIR pulse.
View Article and Find Full Text PDFThe increasing availability of X-ray free-electron lasers (XFELs) has catalyzed the development of single-object structural determination and of structural dynamics tracking in real-time. Disentangling the molecular-level reactions triggered by the interaction with an XFEL pulse is a fundamental step towards developing such applications. Here we report real-time observations of XFEL-induced electronic decay via short-lived transient electronic states in the diiodomethane molecule, using a femtosecond near-infrared probe laser.
View Article and Find Full Text PDFCoulomb explosion of diiodomethane CHI molecules irradiated by ultrashort and intense X-ray pulses from SACLA, the Japanese X-ray free electron laser facility, was investigated by multi-ion coincidence measurements and self-consistent charge density-functional-based tight-binding (SCC-DFTB) simulations. The diiodomethane molecule, containing two heavy-atom X-ray absorbing sites, exhibits a rather different charge generation and nuclear motion dynamics compared to iodomethane CHI with only a single heavy atom, as studied earlier. We focus on charge creation and distribution in CHI in comparison to CHI.
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