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  • Dioctadecyldimethylammonium bromide, a surfactant model for the cell membrane: Importance of microscopic dynamics
    Struct. Dyn. (IF 3.216) Pub Date : 2020-09-22
    V. K. Sharma; H. Srinivasan; V. García Sakai; S. Mitra

    Cationic lipid membranes have recently attracted huge attention both from a fundamental point of view and due to their practical applications in drug delivery and gene therapy. The dynamical behavior of the lipids in the membrane is a key parameter controlling various physiological processes and drug release kinetics. Here, we review the dynamical and thermotropic phase behavior of an archetypal cationic

  • The TRIXS end-station for femtosecond time-resolved resonant inelastic x-ray scattering experiments at the soft x-ray free-electron laser FLASH
    Struct. Dyn. (IF 3.216) Pub Date : 2020-09-16
    S. Dziarzhytski; M. Biednov; B. Dicke; A. Wang; P. S. Miedema; R. Y. Engel; J. O. Schunck; H. Redlin; H. Weigelt; F. Siewert; C. Behrens; M. Sinha; A. Schulte; B. Grimm-Lebsanft; S. G. Chiuzbăian; W. Wurth; M. Beye; M. Rübhausen; G. Brenner

    We present the experimental end-station TRIXS dedicated to time-resolved soft x-ray resonant inelastic x-ray scattering (RIXS) experiments on solid samples at the free-electron laser FLASH. Using monochromatized ultrashort femtosecond XUV/soft x-ray photon pulses in combination with a synchronized optical laser in a pump-probe scheme, the TRIXS setup allows measuring sub-picosecond time-resolved high-resolution

  • Simultaneous two-color snapshot view on ultrafast charge and spin dynamics in a Fe-Cu-Ni tri-layer
    Struct. Dyn. (IF 3.216) Pub Date : 2020-09-22
    Benedikt Rösner; Boris Vodungbo; Valentin Chardonnet; Florian Döring; Vitaliy A. Guzenko; Marcel Hennes; Armin Kleibert; Maxime Lebugle; Jan Lüning; Nicola Mahne; Aladine Merhe; Denys Naumenko; Ivaylo P. Nikolov; Ignacio Lopez-Quintas; Emanuele Pedersoli; Primož R. Ribič; Tatiana Savchenko; Benjamin Watts; Marco Zangrando; Flavio Capotondi; Christian David; Emmanuelle Jal

    Ultrafast phenomena on a femtosecond timescale are commonly examined by pump-probe experiments. This implies multiple measurements, where the sample under investigation is pumped with a short light pulse and then probed with a second pulse at various time delays to follow its dynamics. Recently, the principle of streaking extreme ultraviolet (XUV) pulses in the temporal domain has enabled recording

  • Repetitive non-thermal melting as a timing monitor for femtosecond pump/probe X-ray experiments
    Struct. Dyn. (IF 3.216) Pub Date : 2020-09-22
    Å. U. J. Bengtsson; J. C. Ekström; Xiaocui Wang; A. Jurgilaitis; Van-Thai Pham; D. Kroon; J. Larsson

    Time-resolved optical pump/X-ray probe experiments are often used to study structural dynamics. To ensure high temporal resolution, it is necessary to monitor the timing between the X-ray pulses and the laser pulses. The transition from a crystalline solid material to a disordered state in a non-thermal melting process can be used as a reliable timing monitor. We have performed a study of the non-thermal

  • Characterization of a time-resolved electron microscope with a Schottky field emission gun
    Struct. Dyn. (IF 3.216) Pub Date : 2020-10-01
    Pavel K. Olshin; Marcel Drabbels; Ulrich J. Lorenz

    The rapid growth of the field of time-resolved and ultrafast electron microscopy has been accompanied by the active development of new instrumentation. Recently, time-resolved microscopes equipped with a field emission gun have been introduced, demonstrating great potential for experiments that benefit from the high brightness and coherence of the electron source. Here, we describe a straightforward

  • Transient magnetic gratings on the nanometer scale
    Struct. Dyn. (IF 3.216) Pub Date : 2020-09-08
    D. Weder; C. von Korff Schmising; C. M. Günther; M. Schneider; D. Engel; P. Hessing; C. Strüber; M. Weigand; B. Vodungbo; E. Jal; X. Liu; A. Merhe; E. Pedersoli; F. Capotondi; J. Lüning; B. Pfau; S. Eisebitt

    Laser-driven non-local electron dynamics in ultrathin magnetic samples on a sub-10 nm length scale is a key process in ultrafast magnetism. However, the experimental access has been challenging due to the nanoscopic and femtosecond nature of such transport processes. Here, we present a scattering-based experiment relying on a laser-induced electro- and magneto-optical grating in a Co/Pd ferromagnetic

  • Role of intracellular water in the normal-to-cancer transition in human cells—insights from quasi-elastic neutron scattering
    Struct. Dyn. (IF 3.216) Pub Date : 2020-09-08
    M. P. M. Marques; A. L. M. Batista de Carvalho; A. P. Mamede; A. Dopplapudi; V. García Sakai; L. A. E. Batista de Carvalho

    The transition from normal to malignant state in human cells is still a poorly understood process. Changes in the dynamical activity of intracellular water between healthy and cancerous human cells were probed as an innovative approach for unveiling particular features of malignancy and identifying specific reporters of cancer. Androgen-unresponsive prostate and triple-negative breast carcinomas were

  • Real-time tracking of protein unfolding with time-resolved x-ray solution scattering
    Struct. Dyn. (IF 3.216) Pub Date : 2020-09-22
    L. Henry; M. R. Panman; L. Isaksson; E. Claesson; I. Kosheleva; R. Henning; S. Westenhoff; O. Berntsson

    The correct folding of proteins is of paramount importance for their function, and protein misfolding is believed to be the primary cause of a wide range of diseases. Protein folding has been investigated with time-averaged methods and time-resolved spectroscopy, but observing the structural dynamics of the unfolding process in real-time is challenging. Here, we demonstrate an approach to directly

  • Anomalous sub-diffusion of water in biosystems: From hydrated protein powders to concentrated protein solution to living cells
    Struct. Dyn. (IF 3.216) Pub Date : 2020-10-12
    Rui Li; Zhuo Liu; Like Li; Juan Huang; Takeshi Yamada; Victoria García Sakai; Pan Tan; Liang Hong

    Water is essential to life and its translational motion in living systems mediates various biological processes, including transportation of function-required ingredients and facilitating the interaction between biomacromolecules. By combining neutron scattering and isotopic labeling, the present work characterizes translational motion of water on a biomolecular surface, in a range of systems: a hydrated

  • Enhanced dynamics in the anomalous melting regime of DMPG lipid membranes
    Struct. Dyn. (IF 3.216) Pub Date : 2020-10-16
    Elizabeth G. Kelley; Michihiro Nagao; Paul D. Butler; Lionel Porcar; Bela Farago

    Like many soft materials, lipids undergo a melting transition associated with a significant increase in their dynamics. At temperatures below the main melting transition (Tm), all molecular and collective dynamics are suppressed, while above Tm the alkyl tail motions, lipid diffusivity, and collective membrane undulations are at least an order of magnitude faster. Here we study the collective dynamics

  • Shear-induced ordering in liquid microjets seen by x-ray cross correlation analysis
    Struct. Dyn. (IF 3.216) Pub Date : 2020-10-16
    V. Markmann; M. Dartsch; J. Valerio; L. Frenzel; I. Lokteva; M. Walther; F. Westermeier; G. Grübel; F. Lehmkühler

    We applied shear to a silica nanoparticle dispersion in a microfluidic jet device and observed direction-dependent structure along and across the flow direction. The asymmetries of the diffraction patterns were evaluated by x-ray cross correlation analysis. For different Rayleigh nozzle sizes and shapes, we measured the decay of the shear-induced ordering after the cessation of the shear. At large

  • Perspectives on single particle imaging with x rays at the advent of high repetition rate x-ray free electron laser sources.
    Struct. Dyn. (IF 3.216) Pub Date : 2020-08-06
    Johan Bielecki,Filipe R N C Maia,Adrian P Mancuso

    X-ray free electron lasers (XFELs) now routinely produce millijoule level pulses of x-ray photons with tens of femtoseconds duration. Such x-ray intensities gave rise to the idea that weakly scattering particles—perhaps single biomolecules or viruses—could be investigated free of radiation damage. Here, we examine elements from the past decade of so-called single particle imaging with hard XFELs. We

  • Simulation of time-resolved x-ray absorption spectroscopy of ultrafast dynamics in particle-hole-excited 4‐(2-thienyl)-2,1,3-benzothiadiazole
    Struct. Dyn. (IF 3.216) Pub Date : 2020-07-06
    Khadijeh Khalili; Ludger Inhester; Caroline Arnold; Anders S. Gertsen; Jens Wenzel Andreasen; Robin Santra

    To date, alternating co-polymers based on electron-rich and electron-poor units are the most attractive materials to control functionality of organic semiconductor layers in which ultrafast excited-state processes play a key role. We present a computational study of the photoinduced excited-state dynamics of the 4-(2-thienyl)-2,1,3-benzothiadiazole (BT-1T) molecule, which is a common building block

  • Origin of core-to-core x-ray emission spectroscopy sensitivity to structural dynamics
    Struct. Dyn. (IF 3.216) Pub Date : 2020-07-06
    Morgane Vacher; Kristjan Kunnus; Mickaël G. Delcey; Kelly J. Gaffney; Marcus Lundberg

    Recently, coherent structural dynamics in the excited state of an iron photosensitizer was observed through oscillations in the intensity of Kα x-ray emission spectroscopy (XES). Understanding the origin of the unexpected sensitivity of core-to-core transitions to structural dynamics is important for further development of femtosecond time-resolved XES methods and, we believe, generally necessary for

  • Water structure near the surface of Weyl semimetals as catalysts in photocatalytic proton reduction
    Struct. Dyn. (IF 3.216) Pub Date : 2020-05-12
    Jure Gujt; Peter Zimmer; Frederik Zysk; Vicky Süß; Claudia Felser; Matthias Bauer; Thomas D. Kühne

    In this work, second-generation Car–Parrinello-based mixed quantum-classical mechanics molecular dynamics simulations of small nanoparticles of NbP, NbAs, TaAs, and 1T-TaS2 in water are presented. The first three materials are topological Weyl semimetals, which were recently discovered to be active catalysts in photocatalytic water splitting. The aim of this research was to correlate potential differences

  • Ultrafast x-ray and electron scattering of free molecules: A comparative evaluation.
    Struct. Dyn. (IF 3.216) Pub Date : 2020-06-23
    Lingyu Ma,Haiwang Yong,Joseph D Geiser,Andrés Moreno Carrascosa,Nathan Goff,Peter M Weber

    Resolving gas phase molecular motions with simultaneous spatial and temporal resolution is rapidly coming within the reach of x-ray Free Electron Lasers (XFELs) and Mega-electron-Volt (MeV) electron beams. These two methods enable scattering experiments that have yielded fascinating new results, and while both are important methods for determining transient molecular structures in photochemical reactions

  • Method for developing a sub-10 fs ultrafast electron diffraction technology
    Struct. Dyn. (IF 3.216) Pub Date : 2020-06-09
    Hyun Woo Kim; In Hyung Baek; Junho Shin; Sunjeong Park; Hyeon Sang Bark; Key Young Oang; Kyu-Ha Jang; Kitae Lee; Nikolay Vinokurov; Young Uk Jeong

    The experimental observation of femtosecond dynamics in atoms and molecules by stroboscopic technologies utilizing x ray or electron flashes has attracted much attention and has rapidly developed. We propose a feasible ultrafast electron diffraction (UED) technology with high brightness and a sub-10 fs temporal resolution. We previously demonstrated a UED system with an overall temporal resolution

  • Fluctuation suppression in microgels by polymer electrolytes
    Struct. Dyn. (IF 3.216) Pub Date : 2020-06-15
    S. Pasini; S. Maccarrone; N. K. Székely; L. R. Stingaciu; A. P. H. Gelissen; W. Richtering; M. Monkenbusch; O. Holderer

    Structural details of thermoresponsive, cationically poly(N-iso-propylacrylamide-co-methacrylamido propyl trimethyl ammonium chloride) microgels and the influence of the anionic electrolyte polystyrene sulfonate (PSS) on the internal structure and dynamics of the cationic microgels have been studied with a combination of small angle neutron scattering (SANS) and neutron spin echo (NSE) spectroscopy

  • Imaging plasma formation in isolated nanoparticles with ultrafast resonant scattering.
    Struct. Dyn. (IF 3.216) Pub Date : 2020-06-18
    Daniela Rupp,Leonie Flückiger,Marcus Adolph,Alessandro Colombo,Tais Gorkhover,Marion Harmand,Maria Krikunova,Jan Philippe Müller,Tim Oelze,Yevheniy Ovcharenko,Maria Richter,Mario Sauppe,Sebastian Schorb,Rolf Treusch,David Wolter,Christoph Bostedt,Thomas Möller

    We have recorded the diffraction patterns from individual xenon clusters irradiated with intense extreme ultraviolet pulses to investigate the influence of light-induced electronic changes on the scattering response. The clusters were irradiated with short wavelength pulses in the wavelength regime of different 4d inner-shell resonances of neutral and ionic xenon, resulting in distinctly different

  • Structural dynamics of incommensurate charge-density waves tracked by ultrafast low-energy electron diffraction.
    Struct. Dyn. (IF 3.216) Pub Date : 2020-06-22
    G Storeck,J G Horstmann,T Diekmann,S Vogelgesang,G von Witte,S V Yalunin,K Rossnagel,C Ropers

    We study the non-equilibrium structural dynamics of the incommensurate and nearly commensurate charge-density wave (CDW) phases in 1T- TaS 2. Employing ultrafast low-energy electron diffraction with 1 ps temporal resolution, we investigate the ultrafast quench and recovery of the CDW-coupled periodic lattice distortion (PLD). Sequential structural relaxation processes are observed by tracking the intensities

  • Determination of the dehydration pathway in a flexible metal-organic framework by dynamic in situ x-ray diffraction.
    Struct. Dyn. (IF 3.216) Pub Date : 2020-06-23
    Ian M Walton,Jordan M Cox,Shea D Myers,Cassidy A Benson,Travis B Mitchell,Gage S Bateman,Eric D Sylvester,Yu-Sheng Chen,Jason B Benedict

    Understanding guest exchange processes in metal–organic frameworks is an important step toward the rational design of functional materials with tailor-made properties. The dehydration of the flexible metal-organic framework [Co(AIP)(bpy)0.5(H2O)]•2H2O was studied by novel in situ dynamic x-ray diffraction techniques. The complex mechanism of dehydration, along with the as-yet unreported metastable

  • Imaging phonon dynamics with ultrafast electron microscopy: Kinematical and dynamical simulations.
    Struct. Dyn. (IF 3.216) Pub Date : 2020-04-17
    Daniel X Du,David J Flannigan

    Ultrafast x-ray and electron scattering techniques have proven to be useful for probing the transient elastic lattice deformations associated with photoexcited coherent acoustic phonons. Indeed, femtosecond electron imaging using an ultrafast electron microscope (UEM) has been used to directly image the influence of nanoscale structural and morphological discontinuities on the emergence, propagation

  • Controlled beams of shock-frozen, isolated, biological and artificial nanoparticles.
    Struct. Dyn. (IF 3.216) Pub Date : 2020-04-17
    Amit K Samanta,Muhamed Amin,Armando D Estillore,Nils Roth,Lena Worbs,Daniel A Horke,Jochen Küpper

    X-ray free-electron lasers promise diffractive imaging of single molecules and nanoparticles with atomic spatial resolution. This relies on the averaging of millions of diffraction patterns of identical particles, which should ideally be isolated in the gas phase and preserved in their native structure. Here, we demonstrated that polystyrene nanospheres and Cydia pomonella granulovirus can be transferred

  • A tool for visualizing protein motions in time-resolved crystallography
    Struct. Dyn. (IF 3.216) Pub Date : 2020-04-01
    Cecilia Wickstrand, Gergely Katona, Takanori Nakane, Przemyslaw Nogly, Joerg Standfuss, Eriko Nango, Richard Neutze

    Time-resolved serial femtosecond crystallography (TR-SFX) at an x-ray free electron laser enables protein structural changes to be imaged on time-scales from femtoseconds to seconds. It can, however, be difficult to grasp the nature and timescale of global protein motions when structural changes are not isolated near a single active site. New tools are, therefore, needed to represent the global nature

  • Ultrafast electron imaging of surface charge carrier dynamics at low voltage
    Struct. Dyn. (IF 3.216) Pub Date : 2020-03-30
    Jianfeng Zhao, Osman M. Bakr, Omar F. Mohammed

    The performance of optoelectronic devices strongly depends on charge carrier dynamics on top of surfaces of the absorber layers. Unfortunately, this information cannot be selectively probed using conventional ultrafast laser spectroscopic methods, due to the large penetration depth (tens of nm to μm) of the photon pulses in the pump-probe configurations. Therefore, ultrafast time-resolved approaches

  • Unconventional picosecond strain pulses resulting from the saturation of magnetic stress within a photoexcited rare earth layer
    Struct. Dyn. (IF 3.216) Pub Date : 2020-03-27
    A. von Reppert, M. Mattern, J.-E. Pudell, S. P. Zeuschner, K. Dumesnil, M. Bargheer

    Optical excitation of spin-ordered rare earth metals triggers a complex response of the crystal lattice since expansive stresses from electron and phonon excitations compete with a contractive stress induced by spin disorder. Using ultrafast x-ray diffraction experiments, we study the layer specific strain response of a dysprosium film within a metallic heterostructure upon femtosecond laser-excitation

  • Single-particle imaging by x-ray free-electron lasers—How many snapshots are needed?
    Struct. Dyn. (IF 3.216) Pub Date : 2020-03-20
    I. Poudyal, M. Schmidt, P. Schwander

    X-ray free-electron lasers (XFELs) open the possibility of obtaining diffraction information from a single biological macromolecule. This is because XFELs can generate extremely intense x-ray pulses that are so short that diffraction data can be collected before the sample is destroyed. By collecting a sufficient number of single-particle diffraction patterns, the three-dimensional electron density

  • Ultrafast dynamics of photo-excited 2-thiopyridone: Theoretical insights into triplet state population and proton transfer pathways
    Struct. Dyn. (IF 3.216) Pub Date : 2020-03-17
    Jesper Norell, Michael Odelius, Morgane Vacher

    Ultrafast non-adiabatic dynamics of the small heteroaromatic compound 2-thiopyridone has been studied with surface hopping simulations based on multi-configurational quantum chemistry. Initial excitation of the bright S 2 ( π , π * ) state is found to promptly relax to S 1 ( n ,   π *) through in-plane motion. The subsequent dynamics are oppositely driven by out-of-plane motion, which results in both

  • Secondary structure effects on internal proton transfer in poly-peptides
    Struct. Dyn. (IF 3.216) Pub Date : 2020-03-17
    M. Bouakil, F. Chirot, M. Girod, P. Dugourd, L. MacAleese

    A pump–probe approach was designed to determine the internal proton transfer (PT) rate in a series of poly-peptide radical cations containing both histidine and tryptophan. The proton transfer is driven by the gas-phase basicity difference between residues. The fragmentation scheme indicates that the gas-phase basicity of histidine is lower than that of radical tryptophan so that histidine is always

  • Nanoscale thermal transport across an GaAs/AlGaAs heterostructure interface
    Struct. Dyn. (IF 3.216) Pub Date : 2020-03-17
    Matthew Gorfien, Hailong Wang, Long Chen, Hamidreza Rahmani, Junxiao Yu, Pengfei Zhu, Jie Chen, Xuan Wang, Jianhua Zhao, Jianming Cao

    We studied the thermal transport across a GaAs/AlGaAs interface using time-resolved Reflection High Energy Electron Diffraction. The lattice temperature change of the GaAs nanofilm was directly monitored and numerically