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The possibility to predict, characterize and minimize the presence of spurious harmonic content in the longitudinal profile of high brightness electron beams, namely the microbunching instability, has become vital to ensure accurate modeling and reliable operation of radiofrequency and plasma-based linear accelerators such as those driving free-electron lasers. Recently, the impact of intrabeam scattering (IBS) on the instability has been experimentally demonstrated by the authors. This work complements that experimental study by extending existing theories in a self-consistent, piece-wise calculation of IBS in single pass linacs and multi-bend transfer lines. New expressions for the IBS are introduced in two different semi-analytical models of microbunching. The accuracy of the proposed models and the range of beam parameters to which they apply is discussed. The overall modeling turns out to be a fast comprehensive tool for the optimization of linac-driven free-electron lasers.
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http://dx.doi.org/10.1038/s41598-021-87041-0 | DOI Listing |
J Am Chem Soc
September 2025
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza 34149, Trieste, Italy.
Tracking the multifarious ultrafast electronic and structural changes occurring in a molecule during a photochemical transformation is a challenging endeavor that benefits from recent experimental and computational progress in time-resolved techniques. Measurements of valence electronic states, which provide a global picture of the bonding structure of the molecule, and core electronic states, which provide insight into the local environment, traditionally require different approaches and are often studied separately. Here, we demonstrate that X-ray pulses from a seeded free-electron laser (FEL) enable the measurement of high-resolution, time-resolved X-ray photoelectron spectra (XPS) that capture weak satellite states resulting from shake-down processes in a valence-excited molecule.
View Article and Find Full Text PDFPlant Cell Physiol
August 2025
Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan.
Photosystem II (PSII) catalyzes the light-driven oxidation of water, progressing via sequential oxidation states (S-states) of the Mn4CaO5 cluster. Among structural snapshots of intermediate S-states obtained using X-ray free-electron laser (XFEL) crystallography, two-flash XFEL structures assigned to the S3 state reveal an additional oxygen atom (O6) near the O5 site of the cluster, leading to proposals that O6 is incorporated as a new substrate water molecule during the S2 to S3 transition. However, recent re-analyses of the XFEL data highlight potential complications, including conformational heterogeneity, refinement bias, and possible radiation-induced artifacts.
View Article and Find Full Text PDFJ Phys Chem Lett
September 2025
Hylleraas Centre for Quantum Molecular Sciences, Department of Chemistry, UiT The Arctic University of Norway, 9037 Tromsø, Norway.
Chiral systems exhibit unique properties traditionally linked to their asymmetric spatial arrangement. Recently, multiple laser pulses were shown to induce purely electronic chiral states without altering the nuclear configuration. Here, we propose and numerically demonstrate a simpler realization of light-induced electronic chirality that is long-lived and occurs well before the onset of nuclear motion and decoherence.
View Article and Find Full Text PDFIUCrJ
September 2025
Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan.
Structural analysis of the co-crystal between human DNA glycosylase hOGG1 and a light-sensitive substrate analog highlights its utility as a platform for real-time observation of catalytic dynamics.
View Article and Find Full Text PDFEntropy (Basel)
July 2025
Department of Electrical & Electronic Engineering, Faculty of Engineering, Ariel University, Ariel 40700, Israel.
A reduced representation of a dynamical system helps us to understand what the true degrees of freedom of that system are and thus what the possible instabilities are. Here we extend previous work on barotropic flows to the more general non-barotropic flow case and study the implications for variational analysis and conserved quantities of topological significance such as circulation and helicity. In particular we introduce a four-function Eulerian variational principle of non-barotropic flows, which has not been described before.
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