Lensless X-ray imaging provides element-specific nanoscale insights into thick samples beyond the reach of conventional light and electron microscopy. Coherent diffraction imaging (CDI) methods, such as ptychographic tomography, can recover three-dimensional (3D) nanoscale structures but require extensive sample rotation, adding complexity to experiments. X-ray elastic-scattering patterns from a single sample orientation are highly directional and provide limited 3D information about the structure. In contrast to X-ray elastic scattering, X-ray fluorescence is emitted mostly isotropically. However, first-order spatial coherence has traditionally limited nanoscale fluorescence imaging to single-crystalline samples. Here, we demonstrate that intensity correlations of X-ray fluorescence excited by ultrashort X-ray pulses contain 3D structural information of non-periodic, stationary objects. In our experiment, we illuminated a vanadium foil within a sub-200 nm X-ray laser beam focus. Without changing the sample orientation, we recorded 16 distinct specimen projections using detector regions covering different photon incidence angles relative to the X-ray free-electron laser (FEL) beam. The projections varied systematically as the fluorescing volume was translated along an astigmatism, confirming that FEL-induced fluorescence reflects real-space structural changes. Our results establish a new approach for lensless 3D imaging of non-periodic specimens using fluorescence intensity correlations, with broad implications for materials science, chemistry, and nanotechnology.

X-ray Free Electron Lasers (XFEL) are the most advanced pulsed x-ray sources. Their extraordinary pulse parameters promise unique applications. Indeed, several new methods have been developed at XFEL-s. However, no methods are known, which would allow ab initio atomic level structure determination using only a single XFEL pulse. Here, we present experimental results, demonstrating the determination of the 3D atomic structure from data obtained during a single 25 fs XFEL pulse. Parallel measurement of hundreds of Bragg reflections was done by collecting Kossel line patterns of GaAs and GaP. With these measurements, we reached the ultimate temporal limit of the x-ray structure solution possible today. These measurements open the way for studying non-repeatable fast processes and structural transformations in crystals for example measuring the atomic structure of matter at extremely non-ambient conditions or transient structures formed in irreversible physical, chemical, or biological processes. It would also facilitate time resolved pump-probe structural studies making them significantly shorter than traditional serial crystallography.

The JUNGFRAU detector is a well-established hybrid pixel detector developed at the Paul Scherrer Institut (PSI) designed for free-electron laser (FEL) applications. JUNGFRAU features a charge-integrating dynamic gain switching architecture, with three different gain stages and 75 μm pixel pitch. It is widely used at the European X-ray Free-Electron Laser (EuXFEL), a facility which produces high brilliance X-ray pulses at MHz repetition rate in the form of bursts repeating at 10 Hz. In nominal configuration, the detector utilizes only a single memory cell and supports data acquisition up to 2 kHz. This constrains the operation of the detector to a 10 Hz frame rate when combined with the pulsed train structure of the EuXFEL. When configured in so-called burst mode, the JUNGFRAU detector can acquire a series of images into sixteen memory cells at a maximum rate of around 150 kHz. This acquisition scheme is better suited for the time structure of the X-rays as well as the pump laser pulses at the EuXFEL. To ensure confidence in the use of the burst mode at EuXFEL, a wide range of measurements have been performed to characterize the detector, especially to validate the detector alibration procedures. In particular, by analyzing the detector response to varying photon intensity (so called ‘intensity scan’), special attention was given to the characterization of the transitions between gain stages. The detector was operated in both dynamic gain switching and fixed gain modes. Results of these measurements indicate difficulties in the characterization of the detector dynamic gain switching response while operated in burst mode, while no major issues have been found with fixed gain operation. Based on this outcome, fixed gain operation mode with all the memory cells was used during two experiments at EuXFEL, namely in serial femtosecond protein crystallography and Kossel lines measurements. The positive outcome of these two experiments validates the good results previously obtained, and opens the possibility for a wider usage of the detector in burst operation mode, although compromises are needed on the dynamic range.

Single crystals of two organic-inorganic hybrid (OIH) perovskites containing 1,5 pentylenediammonium, [NH3(CH2)5-NH3] MnCl3.47Br0.53 (C5MnCB) and [NH3-(CH2)5-NH3] CoCl2.72Br1.28 (C5CoCB) were grown from solution by evaporation. The structure is investigated by single crystal x-ray diffraction, and infrared and Raman spectroscopy is used to help proper space group selection. The C5MnCB hybrid perovskite crystallizes in the orthorhombic space group Ima2, with unit cell parameters a = 23.9358(11) angstrom, b = 7.4110(3) angstrom, c = 7.1765(4) angstrom, V = 1273.03(11) angstrom 3 and Z = 4. In this sample two types of disorder are found: a preferential substitution of Cl by Br, and a dynamical disorder caused by the rotation of the NH3+ group. The C5CoCB hybrid perovskite crystallizes in the monoclinic space group P21/c, with unit cell parameters a = 7.1914(14) angstrom, b = 16.265(4) angstrom, c = 11.248(2) angstrom, beta = 98.033(7)degrees, V = 1302.7(5) angstrom 3 and Z = 4. In this compound a random Cl-Br occupancy is present. Based on UV-Vis spectroscopy and thermal stability measurements, we suggest possible photovoltaic and visible light photocatalytic applications.

Indexing of Kikuchi and Kossel lines is a crucial step in K-line pattern analysis. Previous approaches mostly rely on the knowledge of unit-cell parameters and experimental geometry. An auto-indexing procedure is introduced that is able to find the unknown lattice, its orientation and the indices of the lines. To achieve this, the unbiased extraction of the precise conical geometrical information from the patterns is combined with existing auto-indexing procedures developed in the field of crystallography. A subsequent lattice-constrained refinement of all lines to the experimental pattern yields reliable lattice and experimental parameters simultaneously. Beyond providing detailed mathematical formulae, the procedure is also demonstrated on an experimental Kossel line pattern.

In this work, the results obtained by single X-ray diffraction (XRD); even if for larger R-factor, are confirmed by another independent technique, one can study the vibrational spectroscopy with symmetry and group theory character tables.This method can be applied on the whole molecule or a part of it, mainly we search for function groups such as H2O, an ionic part such as NH 4+ or metal halide such as (MnBrx).The fine XRD data results five possible solutions for the same molecule with the same chemical formula, although the R-factor values are so close, this method can distinguish between these possible solutions upon the crystal structure.The study of C5H10(NH3)2(MnCl4Br2) results one solution of XRD is confirmed by IR and Raman spectroscopy.The space group of the molecule Ima2 with R= 3.33, The (MnCl4Br2) belongs to D4h of 5 Raman peaks and different 5 IR peaks.The Mn2(MnCl4Br2) is C2, C2h or Cs according To the location of Mn atoms to the octahedral, the suitable solution is C2h which expects 12 IR and another 9 Raman peaks with good agreement with IR and Raman results.

Hybrid perovskites of the formula A2MX4, A: ammonium substituted organic cation, M: a divalent metal ion and X: a halogen (Cl, Br, I) have attracted considerable attention recently.Their applications include lead-free perovskite solar cell [1], optoelectronic, exitonic and self-assembly quantum well.The properties of these hybrid perovskites OIHs are functions of A, M and X and there are possibilities to tailor the structure, physical and chemical properties according to the application needed [2-3].The Co hybrid perovskite is a promising material for lead-free perovskite solar cell applications.Mn organic-inorganic hybrid can be used as catalysis and ultraviolet absorbing materials.Cu hybrid can be used in the application of self-assembly quantum well as well as leadfree perovskite solar cell [4].Some of these materials posses reversible phase transition that may find application as sensors and data storage devises.The presenter has deposited about 15 of these novel hybrid perovskite materials at Cambridge Crystallographic Data Center (CCDC).For further investigation and characterization of diammonium hybrid perovskite materials xrf/xafs has been performed.Figure 1.Left panel crystal structure of [NH3(CH2)5NH3]MnCl2Br2 at 240 K and right panel layered structure of [NH3(CH2)5NH3]CoCl2Br2 at T = 300 K.

Atomic resolution X-ray holography can be realized by using the atoms of the sample as inside sources or inside detectors. However, until now there were only very few experiments in which the atoms played the role of inside sources. The reason is twofold: (i) technically, inside-detector experiments are much easier and faster; (ii) by using atoms as inside detectors one can measure holograms at many energies on the same sample, which helps the reconstruction. This paper shows that, using new technical developments, inside-source holograms can be taken much faster than inside-detector holograms and, by applying a sophisticated evaluation method, high-quality reconstruction from a single-energy hologram can also be obtained.

Ultrafast X-ray imaging on individual fragile specimens such as aerosols 1 , metastable particles 2 , superfluid quantum systems 3 and live biospecimens 4 provides high-resolution information that is inaccessible with conventional imaging techniques. Coherent X-ray diffractive imaging, however, suffers from intrinsic loss of phase, and therefore structure recovery is often complicated and not always uniquely defined 4 , 5 . Here, we introduce the method of in-flight holography, where we use nanoclusters as reference X-ray scatterers to encode relative phase information into diffraction patterns of a virus. The resulting hologram contains an unambiguous three-dimensional map of a virus and two nanoclusters with the highest lateral resolution so far achieved via single shot X-ray holography. Our approach unlocks the benefits of holography for ultrafast X-ray imaging of nanoscale, non-periodic systems and paves the way to direct observation of complex electron dynamics down to the attosecond timescale.

Diffraction before destruction using X-ray free-electron lasers (XFELs) has the potential to determine radiation-damage-free structures without the need for crystallization. This article presents the three-dimensional reconstruction of the Melbournevirus from single-particle X-ray diffraction patterns collected at the LINAC Coherent Light Source (LCLS) as well as reconstructions from simulated data exploring the consequences of different kinds of experimental sources of noise. The reconstruction from experimental data suffers from a strong artifact in the center of the particle. This could be reproduced with simulated data by adding experimental background to the diffraction patterns. In those simulations, the relative density of the artifact increases linearly with background strength. This suggests that the artifact originates from the Fourier transform of the relatively flat background, concentrating all power in a central feature of limited extent. We support these findings by significantly reducing the artifact through background removal before the phase-retrieval step. Large amounts of blurring in the diffraction patterns were also found to introduce diffuse artifacts, which could easily be mistaken as biologically relevant features. Other sources of noise such as sample heterogeneity and variation of pulse energy did not significantly degrade the quality of the reconstructions. Larger data volumes, made possible by the recent inauguration of high repetition-rate XFELs, allow for increased signal-to-background ratio and provide a way to minimize these artifacts. The anticipated development of three-dimensional Fourier-volume-assembly algorithms which are background aware is an alternative and complementary solution, which maximizes the use of data.

Prolonged annealing of pentacene thin films in air leads to the formation of nano- and micro-scale rod-shaped structures at temperatures equal to or higher than 130 degrees C. Scanning electron microscopy measurements indicated their crystalline structure, while UV-vis absorption spectra revealed presence of different species of oxidized pentacene, including 6,13-pentacenequinone. The mechanism of growth of microcrystals from oxidized pentacene molecules is discussed. Raman and UV-vis absorption spectra dependences on film thickness (in 30-300 nm range) and on thermal annealing conditions (in air and nitrogen at ambient pressure at 100 and 150 degrees C) were also studied. These spectra are not largely affected by annealing if it is performed in nitrogen at any of studied temperatures and annealing times (few hours to few days). However, if annealing is performed in air, at temperatures 130 degrees C and higher, changes in spectral features are significant due to film oxidation. (c) 2017 Elsevier Ltd. All rights reserved.

Kossel lines are formed when radiation from point x-ray sources inside a single crystal are diffracted by the crystal itself. In principle, Kossel line patterns contain full information on the crystalline structure: phase and magnitude of the structure factors. The phase is coded into the profile of the lines. Although this was known for a long time, experimental realization has not been presented. In this work we demonstrate experimentally that phases can be directly determined from the profile of the Kossel lines. These measurements are interesting not only theoretically, but they would facilitate structure solution of samples within extreme conditions, such as high pressure, high and low temperatures, high magnetic fields and extremely short times. The parallel measurement of many diffraction lines on a stationary sample will allow a more efficient use of the new generation of x-ray sources the X-ray free electron lasers (XFELs).

We computationally study the resolution limits for three-dimensional coherent x-ray diffractive imaging of heavy, nonbiological systems using Ar clusters as a prototype. We treat electronic and nuclear dynamics on an equal footing and remove the frozen-lattice approximation often used in electronic damage studies. We explore the achievable resolution as a function of pulse parameters (fluence level, pulse duration, and photon energy) and particle size. The contribution of combined lattice and electron dynamics is not negligible even for 2 fs pulses, and the Compton scattering is less deleterious than in biological systems for atomic-scale imaging. Although free-electron scattering represents a significant background, we find that recovery of the original structure is in principle possible with 3 angstrom resolution for particles of 11 nm diameter.

Kossel line patterns contain information on the crystalline structure, such as the magnitude and the phase of Bragg reflections. For technical reasons, most of these patterns are obtained using electron beam excitation, which leads to surface sensitivity that limits the spatial extent of the structural information. To obtain the atomic structure in bulk volumes, X-rays should be used as the excitation radiation. However, there are technical problems, such as the need for high resolution, low noise, large dynamic range, photon counting, two-dimensional pixel detectors and the small spot size of the exciting beam, which have prevented the widespread use of Kossel pattern analysis. Here, an experimental setup is described, which can be used for the measurement of Kossel patterns in a reasonable time and with high resolution to recover structural information.

Single-molecule imaging is one of the main target areas of X-ray free-electron lasers. It relies on the possibility of orienting the large number of low-counting-statistics 2D diffraction patterns taken at random orientations of identical replicas of the sample. This is a difficult process and the low statistics limits the usability of orientation methods and ultimately it could prevent single-molecule imaging. We suggest a new approach, which avoids the orientation process from the diffraction patterns. We propose to determine sample orientation through identifying the direction of ejection fragments. The orientation of the sample is measured together with the diffraction pattern by detecting some fragments of the Coulomb explosion. We show by molecular-dynamics simulations that from the angular distribution of the fragments one can obtain the orientation of the samples.

Single molecule imaging is one of the main target areas of X-ray free electron lasers. It relies on the possibility of orienting the large number of low counting statistics 2D diffraction patterns taken at random orientations of identical replicas of the sample. This is a difficult process and the low statistics limits the usability of orientation methods and ultimately it could prevent single molecule imaging. We suggest a new approach, which avoids the orientation process from the diffraction patterns. In our schema one measures the orientation of the sample together with the diffraction pattern by detecting some fragments of the Coulomb explosion. We show by molecular dynamics simulations that from the angular distribution of the fragments one can obtain the orientation of the samples.