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We report femtosecond Fe K-edge absorption (XAS) and nonresonant X-ray emission (XES) spectra of ferric cytochrome C (Cyt c) upon excitation of the haem (>300 nm) or mixed excitation of the haem and tryptophan (

We use time-resolved hard x-ray diffraction to investigate the structural dynamics of the multiferroic insulator TbMnO$_3$ in the low temperature antiferromagnetic and ferroelectrically ordered phase. The lattice response following photoexcitation at 1.55 eV is detected by measuring the (0 2 4) and (1 3 -5) Bragg reflections. A 0.02% tensile strain, normal to the surface, is seen to arise within 20 - 30 ps. The magnitude of this transient strain is over an order of magnitude lower than that predicted from laser-induced heating, which we attribute to a bottleneck in the energy transfer between the electronic and lattice subsystems. The timescale for the transient expansion is consistent with that of previously reported demagnetization dynamics. We discuss a possible relationship between structural and demagnetization dynamics in TbMnO$_3$, in which photoinduced atomic motion modulates the exchange interaction, leading to a destruction of the magnetic order in the system., Comment: 3 figures, 4 footnotes

Applied physics letters 120(20), 202203 (2022). doi:10.1063/5.0083256, We report generation of ultra-broadband longitudinal acoustic coherent phonon wavepackets in SrTiO$_3$ (STO) with frequency components extending throughout the first Brillouin zone. The wavepackets are efficiently generated in STO using femtosecond infrared laser excitation of an atomically flat 1.6 nm-thick epitaxial SrRuO$_3$ film. We use femtosecond x-ray diffraction at the European X-Ray Free Electron Laser Facility to study the dispersion and damping of phonon wavepackets. The experimentally determined damping constants for multi-THz frequency phonons compare favorably to the extrapolation of a simple ultrasound damping model over several orders of magnitude., Published by American Inst. of Physics, Melville, NY

Dynamical diffraction effects in thin single crystals produce highly monochromatic parallel x-ray beams with a mutual separation of a few microns and a time delay of a few femtoseconds-the so-called echoes. This ultrafast diffraction effect is used at X-Ray Free Electron Lasers in self-seeding schemes to improve beam monochromaticity. Here, we present a coherent x-ray imaging measurement of echoes from Si crystals and demonstrate that a small surface strain can be used to tune their temporal delay. These results represent a first step toward the ambitious goal of strain tailoring new x-ray optics and, conversely, open up the possibility of using ultrafast dynamical diffraction effects to study strain in materials.

The diffraction endstation of the NanoMAX beamline is designed to provide high-flux coherent X-ray nano-beams for experiments requiring many degrees of freedom for sample and detector. The endstation is equipped with high-efficiency Kirkpatrick–Baez mirror focusing optics and a two-circle goniometer supporting a positioning and scanning device, designed to carry a compact sample environment. A robot is used as a detector arm. The endstation, in continued development, has been in user operation since summer 2017.

This work is an overview of the multi-modal hard X-ray nanoprobe beamline at the MAX IV Laboratory. The beamline provides an intense and coherent beam, focused to 40–200 nm in the energy range 5–28 eV., NanoMAX is the first hard X-ray nanoprobe beamline at the MAX IV laboratory. It utilizes the unique properties of the world’s first operational multi-bend achromat storage ring to provide an intense and coherent focused beam for experiments with several methods. In this paper we present the beamline optics design in detail, show the performance figures, and give an overview of the surrounding infrastructure and the operational diffraction endstation.

Strain and defects in crystalline materials are responsible for the distinct mechanical, electric, and magnetic properties of a desired material, making their study an essential task in material characterization, fabrication, and design. Existing techniques for the visualization of strain fields, such as transmission electron microscopy and diffraction, are destructive and limited to thin slices of the materials. On the other hand, nondestructive x-ray imaging methods either have a reduced resolution or are not robust enough for a broad range of applications. Here we present x-ray ptychographic topography, a method for strain imaging, and demonstrate its use on an InSb micropillar after microcompression, where the strained region is visualized with a spatial resolution of 30 nm. Thereby, x-ray ptychographic topography proves itself as a robust nondestructive approach for the imaging of strain fields within bulk crystalline specimens with a spatial resolution of a few tens of nanometers., Physical Review B, 103 (14), ISSN:1098-0121, ISSN:0163-1829, ISSN:1550-235X, ISSN:0556-2805, ISSN:2469-9969, ISSN:1095-3795, ISSN:2469-9950

Long bone mineralization occurs through endochondral ossification, where a cartilage template mineralizes into bone‐like tissue with a hierarchical organization from the whole bone‐scale down to sub‐nano scale. Whereas this process has been extensively studied at the larger length scales, it remains unexplored at some of the smaller length scales. In this study, the changes in morphology, composition, and structure during embryonic mineralization of murine humeri are investigated using a range of high‐resolution synchrotron‐based imaging techniques at several length scales. With micro‐ and nanometer spatial resolution, the deposition of elements and the shaping of mineral platelets are followed. Rapid mineralization of the humeri occurs over approximately four days, where mineral to matrix ratio and calcium content in the most mineralized zone reach adult values shortly before birth. Interestingly, zinc is consistently found to be localized at the sites of ongoing new mineralization. The mineral platelets in the most recently mineralized regions are thicker, longer, narrower, and less aligned compared to those further into the mineralized region. In summary, this study demonstrates a specific spatial distribution of zinc, with highest concentration where new mineral is being deposited and that the newly formed mineral platelets undergo slight reshaping and reorganization during embryonic development., Long bones are largely formed through endochondral ossification, where a cartilage template gradually mineralizes into a bone‐like tissue. However, the characteristics of this mineralization process at the smaller length scales remain unclear. Using a range of high‐resolution synchrotron‐based techniques, distribution of molecular and elemental content, as well as reshaping and reorganization of mineral platelets are visualized.

The structure-function relationship is at the heart of biology, and major protein deformations are correlated to specific functions. For ferrous heme proteins, doming is associated with the respiratory function in hemoglobin and myoglobins. Cytochrome c (Cyt c) has evolved to become an important electron-transfer protein in humans. In its ferrous form, it undergoes ligand release and doming upon photoexcitation, but its ferric form does not release the distal ligand, while the return to the ground state has been attributed to thermal relaxation. Here, by combining femtosecond Fe K-alpha and K-beta X-ray emission spectroscopy (XES) with Fe K-edge X-ray absorption near-edge structure (XANES), we demonstrate that the photocycle of ferric Cyt c is entirely due to a cascade among excited spin states of the iron ion, causing the ferric heme to undergo doming, which we identify. We also argue that this pattern is common to a wide diversity of ferric heme proteins, raising the question of the biological relevance of doming in such proteins.

Single crystal based optics is widely used at X-ray Free-Electron Laser (XFEL) facilities for beam tailoring. Here, we present recent developments in simulations of coherent X-ray wavefront propagation through crystals. In particular, the Laue case of dynamical diffraction has been implemented in Synchrotron Radiation Work- shop (SRW). Various effects due to wavefront transformation of short XFEL pulses have been simulated in the WavePropaGator (WPG) framework. Possible experimental observations of the effects are discussed.

The emergence of new high brilliance and high coherence facilities such as X-ray Free Electron Lasers (XFELs) and 4th generation synchrotrons open a new era in X-ray optics. Dynamical diffraction effects before disregarded are starting to play a role in the beam control of large scale facilities. In the case of XFEL facilities the temporal characteristics of the dynamical diffraction by thin perfect crystals can be used as a tool to generate femtosecond monochromatic pulses, in the case of self-seeding in the hard X-ray regime, but could even be used as method to characterize materials in this temporal range. In this contribution we present the first steps in the understanding of the spatial-displacement dependence of forward beams diffracted by thin crystals. The data collected by this technique is compared with crystal models based in dynamical diffraction theory. This type of study could open a new field to understand low strain materials in the femtosecond regime.

The photoinduced dynamics of ferric Cytochrome c was investigated by ultrafast non-resonant X-ray emission (XES) and X-Ray Absorption (XAS) spectroscopies, and a cascade through high spin states accompanied by heme doming are observed for the first time.

Time-resolved X-ray methods are widely used for monitoring transient intermediates over the course of photochemical reactions. Ultrafast X-ray absorption and emission spectroscopies as well as elastic X-ray scattering deliver detailed electronic and structural information on chemical dynamics in the solution phase. In this work, we describe the opportunities at the Femtosecond X-ray Experiments (FXE) instrument of European XFEL. Guided by the idea of combining spectroscopic and scattering techniques in one experiment, the FXE instrument has completed the initial commissioning phase for most of its components and performed first successful experiments within the baseline capabilities. This is demonstrated by its currently 115 fs (FWHM) temporal resolution to acquire ultrafast X-ray emission spectra by simultaneously recording iron Kα and Kβ lines, next to wide angle X-ray scattering patterns on a photoexcited aqueous solution of [Fe(bpy)3]2+, a transition metal model compound.

Emphasizing in adolescent daily life during the high school period, the article show how the school times are important in their socialization process, with double perspective: on one hand it stress the meanings of the spatial, temporary and interrelated (family, groups, social networks, etc) context; on the other hand, the one that asses the leisure time and the necessity of a leisure education to contribute to the overall development of their personality. In this sense, moreover, the text display part of an investigation project results which field work was done between 2009 and 2011, describing and interpreting the answers from more than 3.600 adolescents (12-17 years old) to the questionnaire elaborated and applied “ad hoc” in educational establishments from the seventeen Autonomous Communities in Spain. Among other things, it allows the investigation about the activities that they do during school days and weekends, interests and expectations in their leisure time, without forgetting their specific problems and the alternatives that should be taken in social and pedagogical key.

Faraday discussions 239, 160 - 179 (2022). doi:10.1039/D2FD00044J, We report a multi-modal study of the electrical, chemical and structural properties of a kesterite thin-film solar cell by combining the spatially-resolved X-ray beam induced current and fluorescence imaging techniques for the evaluation of a fully functional device on a cross-section. The data allowed the correlation of the chemical composition, defects at interfaces and inhomogeneous deposition of the layers with the local charge-collection efficiency of the device. We support our observations with Monte Carlo simulations of high-energy X-ray interactions with the semiconductor device, and finite-volume modeling of the charge-collection efficiency., Published by Soc., Cambridge [u.a.]

The European XFEL is currently the only high-repetition rate hard X-ray free electron laser (FEL) facility in operation worldwide. We significantly improved its capabilities by installing a cascaded Hard X-ray Self-Seeding (HXRSS) system, composed of two single-crystal monochromators. With this system, mJ-level pulses in the photon energy range of 6 -14keV with a bandwidth around 1eV (corresponding to about 1mJ/eV spectral density) were generated. Combined with the burst-mode, multi-MHz repetition rate of the European XFEL accelerator, the cascaded HXRSS setup provides two orders of magnitude higher average spectral brightness than any other FEL facility. At 2.25 MHz repetition rate and photon energies in the 6-7 keV range, we observed for the first time heat-load effects on the HXRSS crystals, substantially altering the spectra of subsequent X-ray pulses. Using the cascaded self-seeding scheme, we successfully reduced this effect to below detection level. These results open up exciting possibilities in a wide range of scientific fields, exploiting the extreme brightness and the narrow bandwidth of HXRSS pulses.