scholarly journals Chemical interactions and dynamics with femtosecond X-ray spectroscopy and the role of X-ray free-electron lasers

2019 ◽  
Vol 377 (2145) ◽  
pp. 20170464 ◽  
Author(s):  
Philippe Wernet
Keyword(s):  
Structural Dynamics ◽  
Free Electron ◽  
Short Pulse ◽  
Exchange Interactions ◽  
X Rays ◽  
Free Electron Lasers ◽  
Substitution Reactions ◽  
X Ray ◽  
Orbital Interactions

X-ray free-electron lasers with intense, tuneable and short-pulse X-ray radiation are transformative tools for the investigation of transition-metal complexes and metalloproteins. This becomes apparent in particular when combining the experimental observables from X-ray spectroscopy with modern theoretical tools for calculations of electronic structures and X-ray spectra from first principles. The combination gives new insights into how charge and spin densities change in chemical reactions and how they determine reactivity. This is demonstrated for the investigations of structural dynamics with metal K-edge absorption spectroscopy, spin states in excited-state dynamics with metal 3p-3d exchange interactions, the frontier-orbital interactions in dissociation and substitution reactions with metal-specific X-ray spectroscopy, and studies of metal oxidation states with femtosecond pulses for ‘probe-before-destroy’ spectroscopy. The role of X-ray free-electron lasers is addressed with thoughts about how they enable ‘bringing back together’ different aspects of the same problem and this is thought to go beyond a conventional review paper where these aspects are formulated in italic font type in a prequel, an interlude and in a sequel. This article is part of the theme issue ‘Measurement of ultrafast electronic and structural dynamics with X-rays'.

The advent of X-ray free electron lasers

Photoniques ◽  
2021 ◽  
pp. 22-26
Author(s):  
Marie-Emmanuelle Couprie
Keyword(s):  
Free Electron ◽  
Peak Power ◽  
Short Pulse ◽  
Far Infrared ◽  
Gain Medium ◽  
High Peak Power ◽  
X Rays ◽  
Free Electron Lasers ◽  
Free Electrons ◽  
X Ray

Free Electron Lasers (FEL) use free electrons in the periodic permanent magnetic field of an undulator as a gain medium. They extend from far infrared to X-rays, they are easily tunable and provide a high peak power. The advent of tunable intense (few mJ) short pulse (down to the attosecond regime) FELs with record multi GW peak power in the X-ray domain enables to explore new scientific areas. These unprecedent X-ray sources come along with versatile performance.

scholarly journals X-Ray Free-Electron Lasers for the Structure and Dynamics of Macromolecules

2019 ◽  
Vol 88 (1) ◽  
pp. 35-58 ◽  
Author(s):  
Henry N. Chapman
Keyword(s):  
Free Electron ◽  
Conformational Dynamics ◽  
Cryogenic Cooling ◽  
X Rays ◽  
Free Electron Lasers ◽  
X Ray ◽  
Virus Particles ◽  
Structure And Dynamics ◽  
Small Crystals ◽  
Serial Crystallography

X-ray free-electron lasers provide femtosecond-duration pulses of hard X-rays with a peak brightness approximately one billion times greater than is available at synchrotron radiation facilities. One motivation for the development of such X-ray sources was the proposal to obtain structures of macromolecules, macromolecular complexes, and virus particles, without the need for crystallization, through diffraction measurements of single noncrystalline objects. Initial explorations of this idea and of outrunning radiation damage with femtosecond pulses led to the development of serial crystallography and the ability to obtain high-resolution structures of small crystals without the need for cryogenic cooling. This technique allows the understanding of conformational dynamics and enzymatics and the resolution of intermediate states in reactions over timescales of 100 fs to minutes. The promise of more photons per atom recorded in a diffraction pattern than electrons per atom contributing to an electron micrograph may enable diffraction measurements of single molecules, although challenges remain.

Accelerator-based X-ray sources: synchrotron radiation, X-ray free electron lasers and beyond

2019 ◽  
Vol 377 (2147) ◽  
pp. 20180231 ◽  
Author(s):  
Tetsuya Ishikawa
Keyword(s):  
Synchrotron Radiation ◽  
Storage Ring ◽  
Free Electron ◽  
Continuous Wave ◽  
Transitional Period ◽  
Light Sources ◽  
X Rays ◽  
Free Electron Lasers ◽  
Beam Emittance ◽  
X Ray

The evolution of synchrotron radiation (SR) sources and related sciences is discussed to explain the ‘generation’ of the SR sources. Most of the contemporary SR sources belong to the third generation, where the storage rings are optimized for the use of undulator radiation. The undulator development allowed to reduction of the electron energy of the storage ring necessary for delivering 10 keV X-rays from the initial 6–8 GeV to the current 3 Gev. Now is the transitional period from the double-bend-achromat lattice-based storage ring to the multi-bend-achromat lattice to achieve much smaller electron beam emittance. Free electron lasers are the other important accelerator-based light sources which recently reached hard X-ray regime by using self-amplified spontaneous emission scheme. Future accelerator-based X-ray sources should be continuous wave X-ray free electron lasers and pulsed X-ray free electron lasers. Some pathways to reach the future case are discussed. This article is part of the theme issue ‘Fifty years of synchrotron science: achievements and opportunities’.

scholarly journals Time-Resolved Macromolecular Crystallography at Pulsed X-ray Sources

2019 ◽  
Vol 20 (6) ◽  
pp. 1401 ◽  
Author(s):  
Marius Schmidt
Keyword(s):  
Structural Biology ◽  
Free Electron ◽  
Reaction Dynamics ◽  
X Rays ◽  
Free Electron Lasers ◽  
Macromolecular Crystallography ◽  
Time Resolved ◽  
X Ray ◽  
Methodological Aspects

The focus of structural biology is shifting from the determination of static structures to the investigation of dynamical aspects of macromolecular function. With time-resolved macromolecular crystallography (TRX), intermediates that form and decay during the macromolecular reaction can be investigated, as well as their reaction dynamics. Time-resolved crystallographic methods were initially developed at synchrotrons. However, about a decade ago, extremely brilliant, femtosecond-pulsed X-ray sources, the free electron lasers for hard X-rays, became available to a wider community. TRX is now possible with femtosecond temporal resolution. This review provides an overview of methodological aspects of TRX, and at the same time, aims to outline the frontiers of this method at modern pulsed X-ray sources.

On-line monitoring of the spatial properties of hard X-ray free-electron lasers based on a grating splitter

2019 ◽  
Vol 26 (3) ◽  
pp. 619-628 ◽  
Author(s):  
Wenqiang Hua ◽  
Guangzhao Zhou ◽  
Zhe Hu ◽  
Shumin Yang ◽  
Keliang Liao ◽  
...  
Keyword(s):  
Free Electron ◽  
Incident Beam ◽  
Single Pulse ◽  
X Rays ◽  
Free Electron Lasers ◽  
Spatial Characteristics ◽  
X Ray ◽  
First Order ◽  
Spatial Properties ◽  
On Line

X-ray free-electron lasers (XFELs) play an increasingly important role in addressing the new scientific challenges relating to their high brightness, high coherence and femtosecond time structure. As a result of pulse-by-pulse fluctuations, the pulses of an XFEL beam may demonstrate subtle differences in intensity, energy spectrum, coherence, wavefront, etc., and thus on-line monitoring and diagnosis of a single pulse are required for many XFEL experiments. Here a new method is presented, based on a grating splitter and bending-crystal analyser, for single-pulse on-line monitoring of the spatial characteristics including the intensity profile, coherence and wavefront, which was suggested and applied experimentally to the temporal diagnosis of an XFEL single pulse. This simulation testifies that the intensity distribution, coherence and wavefront of the first-order diffracted beam of a grating preserve the properties of the incident beam, by using the coherent mode decomposition of the Gaussian–Schell model and Fourier optics. Indicatively, the first-order diffraction of appropriate gratings can be used as an alternative for on-line monitoring of the spatial properties of a single pulse without any characteristic deformation of the principal diffracted beam. However, an interesting simulation result suggests that the surface roughness of gratings will degrade the spatial characteristics in the case of a partially coherent incident beam. So, there exists a suitable roughness value for non-destructive monitoring of the spatial properties of the downstream beam, which depends on the specific optical path. Here, experiments based on synchrotron radiation X-rays are carried out in order to verify this method in principle. The experimental results are consistent with the theoretical calculations.

scholarly journals The measurement of ultrafast electronic and structural dynamics with X-rays

2019 ◽  
Vol 377 (2145) ◽  
pp. 20170481 ◽  
Author(s):  
J. P. Marangos
Keyword(s):  
Structural Dynamics ◽  
High Harmonic ◽  
High Impact ◽  
X Rays ◽  
Free Electron Lasers ◽  
Theme Issue ◽  
X Ray ◽  
Ultrafast Science ◽  
Photon Sources ◽  
New Generation

In this theme issue, leading researchers discuss recent work on the measurement of ultrafast electronic and structural dynamics in matter using a new generation of short duration X-ray photon sources. These photon sources, based upon high harmonic generation from lasers and X-ray free-electron lasers, look set to have a high impact on ultrafast science. This article is part of the theme issue ‘Measurement of ultrafast electronic and structural dynamics with X-rays’.

Thorough small-angle X-ray scattering analysis of the instability of liquid micro-jets in air

2013 ◽  
Vol 21 (1) ◽  
pp. 193-202 ◽  
Author(s):  
Benedetta Marmiroli ◽  
Fernando Cacho-Nerin ◽  
Barbara Sartori ◽  
Javier Pérez ◽  
Heinz Amenitsch
Keyword(s):  
Small Angle ◽  
Free Electron ◽  
Liquid Jets ◽  
Liquid Jet ◽  
X Rays ◽  
Free Electron Lasers ◽  
X Ray ◽  
X Ray Scattering ◽  
Break Up ◽  
Ray Scattering

Liquid jets are of interest, both for their industrial relevance and for scientific applications (more important, in particular for X-rays, after the advent of free-electron lasers that require liquid jets as sample carrier). Instability mechanisms have been described theoretically and by numerical simulation, but confirmed by few experimental techniques. In fact, these are mainly based on cameras, which is limited by the imaging resolution, and on light scattering, which is hindered by absorption, reflection, Mie scattering and multiple scattering due to complex air/liquid interfaces during jet break-up. In this communication it is demonstrated that synchrotron small-angle X-ray scattering (SAXS) can give quantitative information on liquid jet dynamics at the nanoscale, by detecting time-dependent morphology and break-up length. Jets ejected from circular tubes of different diameters (100–450 µm) and speeds (0.7–21 m s−1) have been explored to cover the Rayleigh and first wind-induced regimes. Various solvents (water, ethanol, 2-propanol) and their mixtures have been examined. The determination of the liquid jet behaviour becomes essential, as it provides background data in subsequent studies of chemical and biological reactions using SAXS or X-ray diffraction based on synchrotron radiation and free-electron lasers.

scholarly journals Science at X-ray Free Electron Lasers

2021 ◽  
Vol 11 (22) ◽  
pp. 10622
Author(s):  
Kiyoshi Ueda
Keyword(s):  
Free Electron ◽  
Short Pulse ◽  
Free Electron Lasers ◽  
X Ray ◽  
Power Densities

X-ray Free Electron Lasers (FELs) deliver coherent X-ray pulses, combining unprecedented power densities of up to 1020 W/cm2 and extremely short pulse durations down to hundreds of attoseconds [...]

Diamond crystal optics for self-seeding of hard X-rays in X-ray free-electron lasers

2013 ◽  
Vol 33 ◽  
pp. 1-4 ◽  
Author(s):  
S. Stoupin ◽  
V.D. Blank ◽  
S.A. Terentyev ◽  
S.N. Polyakov ◽  
V.N. Denisov ◽  
...  
Keyword(s):  
Free Electron ◽  
Diamond Crystal ◽  
X Rays ◽  
Free Electron Lasers ◽  
Crystal Optics ◽  
X Ray
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