We present a high-pressure/high-temperature cell design suitable for in situ X-ray scattering experiments at pressures up to 100 MPa and temperatures up to 773 K. The high energy X-ray beam is guided through two opposing sapphire windows to enable X-ray reflectivity studies for a wide range of momentum transfer allowing access to atomic length scales. The sample cell is heated by four heating cartridges inserted into the cell body. By measuring the temperature directly in the cell volume, high temperature stability of up to 0.1 K can be achieved. A Bridgman sealing system ensures leak tightness of the sample cell even when corrosive and supercritical fluids are used. Custom-built sample holders accommodate solid substrates of various dimensions up to 12x20 mm2 (W × L). The performance of the cell is demonstrated by visual observation of the supercritical phase transition of H2O and an X-ray reflectivity study of octadecyltrichlorosilane coated silicon wafers in contact with sub- and supercritical carbon dioxide. Here, formation of a liquid CO2 layer in the subcritical regime is observed that vanishes at supercritical conditions.

A von Hámos spectrometer has been implemented in the vacuum interaction chamber 1 of the High Energy Density instrument at the European X-ray Free-Electron Laser facility. This setup is dedicated, but not necessarily limited, to X-ray spectroscopy measurements of samples exposed to static compression using a diamond anvil cell. Si and Ge analyser crystals with different orientations are available for this setup, covering the hard X-ray energy regime with a sub-eV energy resolution. The setup was commissioned by measuring various emission spectra of free-standing metal foils and oxide samples in the energy range between 6 and 11 keV as well as low momentum-transfer inelastic X-ray scattering from a diamond sample. Its capabilities to study samples at extreme pressures and temperatures have been demonstrated by measuring the electronic spin-state changes of (Fe0.5Mg0.5)O, contained in a diamond anvil cell and pressurized to 100 GPa, via monitoring the Fe Kβ fluorescence with a set of four Si(531) analyser crystals at close to melting temperatures. The efficiency and signal-to-noise ratio of the spectrometer enables valence-to-core emission signals to be studied and single pulse X-ray emission from samples in a diamond anvil cell to be measured, opening new perspectives for spectroscopy in extreme conditions research.

Fast and efficient (resonant) X-ray emission spectroscopy setup for the electronic structure at lower mantle conditions: high spin in laser-heated FeCO 3 and a two-step spin transition in pressurized Fe 2 O 3 with increasing valence to core intensity.

Large area manufacturing processes of thin films such as large-area vacuum roll-to-roll coating of dielectric and gas permeation barrier layers in industry require a precise control of e.g. film thickness, homogeneity, chemical compositions, crystallinity and surface roughness. In order to determine these properties in real time, hyperspectral imaging is a novel, cost-efficient, and fast tool as in-line technology for large-area quality control. We demonstrate the application of hyperspectral imaging to characterize the thickness of thin films of the multilayer system ZTO/Ag/ITO produced by roll-to-roll magnetron sputtering on 220 mm wide polyethylene terephthalate substrate. X-ray reflectivity measurements are used to determine the thickness gradients of roll-to-roll produced foils with sub nanometer accuracy that serve as ground truth data to train a machine learning model for the interpretation of the hyperspectral imaging spectra. Based on the model, the sub-layer thicknesses on the complete substrate foil area were predicted which demonstrates the capabilities of this approach for large-scale in-line real-time quality control for industrial applications.

The determination of the spin state of iron-bearing compounds at high pressure and temperature is crucial for our understanding of chemical and physical properties of the deep Earth. Studies on the relationship between the coordination of iron and its electronic spin structure in iron-bearing oxides, silicates, carbonates, iron alloys, and other minerals found in the Earth’s mantle and core are scarce because of the technical challenges to simultaneously probe the sample at high pressures and temperatures. We used the unique properties of a pulsed and highly brilliant x-ray free electron laser (XFEL) beam at the High Energy Density (HED) instrument of the European XFEL to x-ray heat and probe samples contained in a diamond anvil cell. We heated and probed with the same x-ray pulse train and simultaneously measured x-ray emission and x-ray diffraction of an FeCO 3 sample at a pressure of 51 GPa with up to melting temperatures. We collected spin state sensitive Fe K β 1 , 3 fluorescence spectra and detected the sample’s structural changes via diffraction, observing the inverse volume collapse across the spin transition. During x-ray heating, the carbonate transforms into orthorhombic Fe 4 C 3 O 12 and iron oxides. Incipient melting was also observed. This approach to collect information about the electronic state and structural changes from samples contained in a diamond anvil cell at melting temperatures and above will considerably improve our understanding of the structure and dynamics of planetary and exoplanetary interiors.

We present a setup exploiting a von Hámos spectrometer in order to study (resonant) X-ray emission of matter exposed to high pressure. The capabilities of this setup are demonstrated for the case of FeO at pressures between 13 GPa and 75 GPa. The setup provides high-quality K β 1,3 X-ray emission spectra at high pressures for iron spin state analysis within minutes and iron valence-to-core spectra in less than one hour. Resonant X-ray emission maps can be obtained on a timescale of one hour with 1.0 eV and in approximately 3 hours with 0.2 eV incident energy resolution. Both K α and K β emission can be utilized to gain L-edge and M-edge-like information, respectively, with the option of measuring both simultaneously. The spin state results on FeO between 13 GPa and 75 GPa are in accordance with recent literature. The structural distortion is reflected in both, valence-to-core spectra and resonant X-ray emission maps, which showcase the great potential of the presented setup. The achieved data acquisition times are promising to couple pressure with temperature by laser heating.

Iron-bearing carbonates play an important role in Earth's carbon cycle. Owing to their stability at mantle conditions, recently discovered iron carbonates with tetrahedrally coordinated carbon atoms are candidates for carbon storage in the deep Earth. The carbonates' iron oxidation and spin state at extreme pressure and temperature conditions contribute to the redox conditions and element partitioning in the deep mantle. By laser heating FeCO3 at pressures of about 83 GPa, Fe43+C3O12 and Fe22+Fe23+C4O13 were synthesized and then investigated by x-ray emission spectroscopy to elucidate their spin state, both in situ and temperature quenched. Our experimental results show both phases in a high-spin state at all pressures and over the entire temperature range investigated, i.e., up to 3000 K. The spin state is conserved after temperature quenching. A formation path is favored where Fe43+C3O12 forms first and then reacts to Fe22+Fe23+C4O13, most likely accompanied by the formation of oxides. Density functional theory calculations of Fe22+Fe23+C4O13 at 80 GPa confirm the experimental findings with both ferric and ferrous iron in high-spin state with antiferromagnetic order at 80 GPa. As the intercrystalline cation partitioning between the Fe-bearing carbonates and the surrounding perovskite and ferropericlase depends on the spin state of the iron, an understanding of the redox conditions prevalent in subducted slab regions in the lower mantle has to take the latter into account. Especially, Fe22+Fe23+C4O13 may play a key role in subducted material in the lower mantle, potentially with a similar role as silicate perovskite.

An X-ray reflectivity study on the interaction of recombinant human resistin (hRes) with fibrillation-prone human islet amyloid polypeptide (hIAPP) at anionic phospholipid Langmuir films as model membranes is presented. Aggregation and amyloid formation of hIAPP is considered the main mechanism of pancreatic β-cell loss in patients with type 2 diabetes mellitus. Resistin shows a chaperone-like ability, but also tends to form aggregates by itself. Resistin and hIAPP cross multiply metabolism pathways. In this study, we researched the potential protective effects of resistin against hIAPP-induced lipid membrane rupture. The results demonstrate that resistin can inhibit or prevent hIAPP adsorption even in the presence of aggregation-promoting negatively charged lipid interfaces. Moreover, we found strong hydrophobic interactions of resistin at the bare buffer-air interface.

We present a surface-sensitive X-ray scattering study on the influence of gaseous and aerolized perfluorocarbons (FCs) on zwitterionic and anionic phospholipid Langmuir films, which serve as a simplified model system of lung surfactants. It was found that small gaseous FC molecules like F-propane and F-butane penetrate phospholipid monolayers and accumulate between the alkyl chains and form islands. This clustering process can trigger the formation of lipid crystallites at low initial surface pressures. In contrast, the large linear FC F-octyl bromide fluidizes membranes, causing a dissolution of crystalline domains. The bicyclic FC F-decalin accumulates between the alkyl chains of 1,2-dipalmitoyl phosphatidylcholine but cannot penetrate the more densely packed 1,2-dipalmitoyl phosphatidic acid films because of its size. The effects of FCs on lung surfactants are discussed in the framework of currently proposed therapeutic methods for acute respiratory distress syndrome using FC gases, vapor, or aerosol ventilation causing monolayer fluidization effects. This study implies that the highly biocompatible and nontoxic FCs could be beneficial in the treatment of lung diseases with injured nonfunctional lung surfactants in a novel approach for ventilation.

Many vital processes that take place in biological cells involve remodeling of lipid membranes. These processes take place in a milieu that is packed with various solutes, ranging from ions and small organic osmolytes to proteins and other macromolecules, occupying about 30% of the available volume. In this work, we investigated how molecular crowding, simulated with the polymer polyethylene glycol (PEG), and the osmolytes urea and trimethylamine-N-oxide (TMAO) affect the equilibration of cubic monoolein structures after a phase transition from a lamellar state induced by an abrupt pressure reduction. In absence of additives, swollen cubic crystallites form after the transition, releasing excess water over several hours. This process is reflected in a decreasing lattice constant and was monitored with small angle X-ray scattering. We found that the osmotic pressure exerted by PEG and TMAO, which are displaced from narrow inter-bilayer spaces, accelerates the equilibration. When the radius of gyration of the added PEG was smaller than the radius of the water channels of the cubic phase, the effect became more pronounced with increasing molecular weight of the polymers. As the release of hydration water from the cubic structures is accompanied by an increasing membrane curvature and a reduction of the interface between lipids and aqueous phase, urea, which has a slight affinity to reside near membrane surfaces, stabilized the swollen crystallites and slowed down the equilibration dynamics. Our results support the view that cellular solutes are important contributors to dynamic membrane processes, as they can accelerate dehydration of inter-bilayer spaces and promote or counteract membrane curvature.

In this paper, we studied fusogenic peptides of class I-III fusion proteins, which are relevant to membrane fusion for certain enveloped viruses, in contact with model lipid membranes. We resolved the vertical structure and examined the adsorption or penetration behavior of the fusogenic peptides at phospholipid Langmuir monolayers with different initial surface pressures with x-ray reflectometry. We show that the fusion loops of tick-borne encephalitis virus (TBEV) glycoprotein E and vesicular stomatitis virus (VSV) G-protein are not able to insert deeply into model lipid membranes, as they adsorbed mainly underneath the headgroups with only limited penetration depths into the lipid films. In contrast, we observed that the hemagglutinin 2 fusion peptide (HA2-FP) and the VSV-transmembrane domain (VSV-TMD) can penetrate deeply into the membranes. However, in the case of VSV-TMD, the penetration was suppressed already at low surface pressures, whereas HA2-FP was able to insert even into highly compressed films. Membrane fusion is accompanied by drastic changes of the membrane curvature. To investigate how the peptides affect the curvature of model lipid membranes, we examined the effect of the fusogenic peptides on the equilibration of cubic monoolein structures after a phase transition from a lamellar state induced by an abrupt hydrostatic pressure reduction. We monitored this process in presence and absence of the peptides with small-angle x-ray scattering and found that HA2-FP and VSV-TMD drastically accelerate the equilibration, while the fusion loops of TBEV and VSV stabilize the swollen state of the lipid structures. In this work, we show that the class I fusion peptide of HA2 penetrates deeply into the hydrophobic region of membranes and is able to promote and accelerate the formation of negative curvature. In contrast, we found that the class II and III fusion loops of TBEV and VSV tend to counteract negative membrane curvature.

The determination of the electronic structure of iron-bearing compounds at high pressure and high temperature (HPHT) conditions is of crucial importance for the understanding of the Earth’s interior and planetary matter. Information on their electronic structure can be obtained by X-ray emission spectroscopy (XES) measurements, where the iron’s Kβ1,3 emission provides information about the spin state and the valence-to-core region focusses on the coordination chemistry around the iron and its electronic state. Furthermore, resonant XES (RXES) at the iron’s K-edge reveals even more detailed information about the electronic structure [1]. We present a setup to investigate the electronic structure of iron-bearing compounds in situ at HPHT conditions using XES and RXES. The HPHT conditions are accomplished by diamond anvil cells (DACs) in combination with a portable double-sided Yb:YAG-laser heating setup [2]. The spectroscopy setup contains a wavelength dispersive von Hamos spectrometer in combination with a Pilatus 100K area detector [3]. This setup provides a full Kβ1,3 emission spectrum including valence-to-core emission in a single shot fashion. In combination with a dedicated sample preparation and use of highly intense synchrotron radiation of beamline P01 at PETRA III, the duration of the measurements is shortened to an extend that in situ XES, including valence-to-core, as well as in situ spin state imaging becomes feasible. The use of miniature diamonds [4] enables RXES measurements at the Fe-K edge. By using different analyzer crystals for the von Hamos spectrometer, simultaneous Kα and Kβ detection are feasible, which provides L-edge and M-edge like information. The presented sample is siderite (FeCO3), which is in focus of recent research as it is a candidate for the carbon storage in the deep Earth. Siderite exhibits a complex chemistry at pressures above 50 GPa and temperatures above 1400 K resulting in the formation of carbonates featuring tetrahedrally coordinated CO4-groups instead of the typical triangular-planar CO3-coordination. These carbonates are well understood on a structural level but information on their electronic structure is scarce [5-7]. We present information on the sample’s spin state at in situ conditions of about 75 GPa and 2000 K XES Kβ1,3 imaging as well as RXES measurements for low and high pressure siderite at ambient temperature conditions for Kα and Kβ emission. [1] M. L. Baker et al., Coordination Chemistry Reviews 345, 182 (2017) [2] G. Spiekermann et al., Journal of Synchroton Radiation, 27, 414 (2020) [3] C. Weis et al., Journal of Analytical Atomic Spectroscopy 34, 384 (2019) [4] S. Petitgirard et al., J. Synchrotron Rad. , 24, 276 (2017) [5] J. Liu et al., Scientific Reports, 5, 7640 (2015) [6] M. Merlini et al., American Mineralogist, 100, 2001, (2015) [7] V. Cerantola et al., Nature Communications 8, 15960 (2017)

The understanding of the microstructure of associated liquids promoted by hydrogen-bonding and constrained by steric hindrance is highly relevant in chemistry, physics, biology and for many aspects of daily life. In this study we use a combination of X-ray diffraction, dielectric spectroscopy and molecular dynamics simulations to reveal temperature induced changes in the microstructure of different octanol isomers, i.e., linear 1-octanol and branched 2-, 3- and 4-octanol. In all octanols, the hydroxyl groups form the basis of chain-, cyclic- or loop-like bonded structures that are separated by outwardly directed alkyl chains. This clustering is analyzed through the scattering pre-peaks observed from X-ray scattering and simulations. The charge ordering which pilots OH aggregation can be linked to the strength of the Debye process observed in dielectric spectroscopy. Interestingly, all methods used here converge to the same interpretation: as one moves from 1-octanol to the branched octanols, the cluster structure evolves from loose large aggregates to a larger number of smaller, tighter aggregates. All alcohols exhibit a peculiar temperature dependence of both the pre-peak and Debye process, which can be understood as a change in microstructure promoted by chain association with increased chain length possibly assisted by ring-opening effects. All these results tend to support the intuitive picture of the entropic constraint provided by branching through the alkyl tails and highlight its capital entropic role in supramolecular assembly.

In recent years, great effort has been taken in science and industry to find novel material-related solutions, which provide improved properties for future technological applications. One of these approaches is the use of fine structured and nanostructured materials. Within the field of wear protection, the use of fine or nanostructured WC-Co powder feedstock in the thermal spray process enables the application of highly wear resistant, thin near net-shape coatings on parts with complex geometries. In this study, the processing of WC-12Co powders by means of High Velocity Oxy-Fuel (HVOF) flame spraying is fundamentally investigated and the results are compared to those obtained with conventional powders. The influence of process parameter and scaling effects on the spray process and the thermo-kinetic particle behavior in the flame, the heating of the substrate as well as on the coating properties, the microstructure, the behavior of elements and phases and the residual stress is discussed comprehensively. The investigations of this work have shown that HVOF spraying of fine and nanostructured WC-12Co powders instead of conventional ones leads to a significant alteration of the thermo-kinetic spray conditions. Under optimized spray conditions, achieved by the use of special spray equipment and statistical design of experiments (DoE), improvements in terms of the economy of the spray process (higher deposition efficiencies) and the mechanical properties (higher microhardness and fracture toughness, lower porosity and roughness) can be achieved.

Knowledge of the microscopic structure of fluids and changes thereof with pressure and temperature is important for the understanding of chemistry and geochemical processes. In this work we investigate the influence of sodium chloride on the hydrogen-bond network in aqueous solution up to supercritical conditions. A combination of in situ X-ray Raman scattering and ab initio molecular dynamics simulations is used to probe the oxygen K-edge of the alkali halide aqueous solution in order to obtain unique information about the oxygen's local coordination around the ions, e.g. solvation-shell structure and the influence of ion pairing. The measured spectra exhibit systematic temperature dependent changes, which are entirely reproduced by calculations on the basis of structural snapshots obtained via ab initio molecular dynamics simulations. Analysis of the simulated trajectories allowed us to extract detailed structural information. This combined analysis reveals a net destabilizing effect of the dissolved ions which is reduced with rising temperature. The observed increased formation of contact ion pairs and occurrence of larger polyatomic clusters at higher temperatures can be identified as a driving force behind the increasing structural similarity between the salt solution and pure water at elevated temperatures and pressures with drawback on the role of hydrogen bonding in the hot fluid. We discuss our findings in view of recent results on hot NaOH and HCl aqueous fluids and emphasize the importance of ion pairing in the interpretation of the microscopic structure of water.

A portable IR fiber laser-heating system, optimized for X-ray emission spectroscopy (XES) and nuclear inelastic scattering (NIS) spectroscopy with signal collection through the radial opening of diamond anvil cells near 90°with respect to the incident X-ray beam, is presented. The system offers double-sided on-axis heating by a single laser source and zero attenuation of incoming X-rays other than by the high-pressure environment. A description of the system, which has been tested for pressures above 100 GPa and temperatures up to 3000 K, is given. The XES spectra of laser-heated Mg0.67Fe0.33O demonstrate the potential to map the iron spin state in the pressure-temperature range of the Earth's lower mantle, and the NIS spectra of laser-heated FeSi give access to the sound velocity of this candidate of a phase inside the Earth's core. This portable system represents one of the few bridges across the gap between laser heating and high-resolution X-ray spectroscopies with signal collection near 90°.

007 is in bed with the nuclear physicist Dr. Christmas Jones in a clear posture.

James Bond is celebrating an anniversary. The 25th film No Time to Die finally makes him the most successful character in film history. When Ian Fleming published the first James Bond novel entitled Casino Royale in 1953, he had no idea just what kind of a character he had created. The British secret agent James Bond, whom Ian Fleming named after an ornithologist from Philadelphia, is one of the best-known film characters ever. He has the habit of introducing himself with the words “The name is Bond, James Bond” and he enjoys a worldwide popularity that could hardly be increased. The double-O number stands for the license to kill, or as his superior M once put it, in the very first Bond movie Dr. No: