Time-resolved x-ray emission spectra from optically ionized helium and neon plasmas

1998 ◽  
Vol 57 (1) ◽  
pp. 982-993 ◽  
Author(s):  
T. E. Glover ◽  
J. K. Crane ◽  
M. D. Perry ◽  
R. W. Lee ◽  
R. W. Falcone
Keyword(s):  
Emission Spectra ◽  
Time Resolved ◽  
X Ray

Time-Resolved Spectroscopy of Scintillation Materials using X-RAY Synchrotron Radiation

1994 ◽  
Vol 348 ◽  
Author(s):  
Andrey N. Belsky ◽  
Vitaly V. Mikhaihin ◽  
Andrey L. Rogalev ◽  
Eduard I. Zinin
Keyword(s):  
Synchrotron Radiation ◽  
Spectral Composition ◽  
Emission Spectra ◽  
Luminescence Spectra ◽  
Electronic Excitations ◽  
Decay Kinetics ◽  
Time Resolved ◽  
X Ray ◽  
Exponential Law ◽  
Kinetics Of

ABSTRACTThe time-resolved luminescence spectra and decay kinetics of BaF2, BGO, and CeF3, were measured with the dissector technique using X-ray synchrotron radiation (SR)of different spectral composition from wiggler mounted at VEPP-3 storage ring (Novosibirsk).Two effects of X-ray excitation energy on the luminescence parameters were observed: modifications of the emission spectrum and acceleration of decay kinetics. Under the excitation by soft X-ray SR the 220 nm emission band for BaF2 is broadened, whereas shorter wavelength part of CeF3 and BGO emission spectra increases. For luminescence decay of excitons and crossluminescence the degree of the deviation from the single exponential law depends on the photon energies and increases under soft X-ray excitation as well. These effects are supposed to be due to the interaction of electronic excitations created after the relaxation of deep core holes.Fast intrinsic luminescence was observed for Cdl2, and CsPbCl3 under X-ray SR excitation. 500 nm band of Cdl2 has characteristic time τ=4.6 ns, whereas 420 nm band of CsPbCl3 shows very fast decay with τ=0.2 ns.

scholarly journals Ultrafast X-ray Photochemistry at European XFEL: Capabilities of the Femtosecond X-ray Experiments (FXE) Instrument

2020 ◽  
Vol 10 (3) ◽  
pp. 995 ◽  
Author(s):  
Dmitry Khakhulin ◽  
Florian Otte ◽  
Mykola Biednov ◽  
Christina Bömer ◽  
Tae-Kyu Choi ◽  
...  
Keyword(s):  
Structural Information ◽  
Emission Spectra ◽  
Photochemical Reactions ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Transient Intermediates ◽  
X Ray Absorption ◽  
Ray Methods ◽  
Ray Scattering

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.

Excited state dynamics of organic semi-conducting materials

2015 ◽  
Vol 177 ◽  
pp. 111-119 ◽  
Author(s):  
Kenneth P. Ghiggino ◽  
Andrew J. Tilley ◽  
Benjamin Robotham ◽  
Jonathan M. White
Keyword(s):  
Excited State ◽  
Conjugated Polymer ◽  
Variable Temperature ◽  
Emission Spectra ◽  
Time Resolved ◽  
Absorption And Emission ◽  
X Ray ◽  
X Ray Crystallography ◽  
Conducting Materials ◽  
Absorption And Emission Spectroscopy

Time-resolved absorption and emission spectroscopy has been applied to investigate the dynamics of excited state processes in oligomer models for semi-conducting organic materials. Following the photo-excitation of a pentamer oligomer that is a model for the conjugated polymer MEH-PPV, an ultrafast component of a few picoseconds is observed for the decay of the initially formed transient species. Variable temperature absorption and emission spectra combined with X-ray crystallography and calculations support the assignment of this rapid relaxation process to an excited state conformational rearrangement from non-planar to more planar molecular configurations. The implications of the results for the overall photophysics of conjugated polymers are considered.

scholarly journals Femtosecond electronic structure response to high intensity XFEL pulses probed by iron X-ray emission spectroscopy

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Roberto Alonso-Mori ◽  
Dimosthenis Sokaras ◽  
Marco Cammarata ◽  
Yuantao Ding ◽  
Yiping Feng ◽  
...  
Keyword(s):  
Electronic Structure ◽  
High Intensity ◽  
Pulse Length ◽  
Rapid Evolution ◽  
Emission Spectra ◽  
Energy Shift ◽  
Spectral Energy ◽  
X Rays ◽  
Time Resolved ◽  
X Ray

Abstract We report the time-resolved femtosecond evolution of the K-shell X-ray emission spectra of iron during high intensity illumination of X-rays in a micron-sized focused hard X-ray free electron laser (XFEL) beam. Detailed pulse length dependent measurements revealed that rapid spectral energy shift and broadening started within the first 10 fs of the X-ray illumination at intensity levels between 1017 and 1018 W cm-2. We attribute these spectral changes to the rapid evolution of high-density photoelectron mediated secondary collisional ionization processes upon the absorption of the incident XFEL radiation. These fast electronic processes, occurring at timescales well within the typical XFEL pulse durations (i.e., tens of fs), set the boundary conditions of the pulse intensity and sample parameters where the widely-accepted ‘probe-before-destroy’ measurement strategy can be adopted for electronic-structure related XFEL experiments.

Microtubule nucleation sequence studied by time-resolved x-ray scattering and electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 766-767
Author(s):  
Eva-Maria Mandelkow ◽  
Eckhard Mandelkow ◽  
Joan Bordas
Keyword(s):  
Electron Microscopy ◽  
Dynamic Equilibrium ◽  
Time Resolved ◽  
X Ray ◽  
Additional Information ◽  
X Ray Scattering ◽  
Low Concentrations ◽  
Microtubule Growth ◽  
Ray Patterns ◽  
Ray Scattering

When a solution of microtubule protein is changed from non-polymerising to polymerising conditions (e.g. by temperature jump or mixing with GTP) there is a series of structural transitions preceding microtubule growth. These have been detected by time-resolved X-ray scattering using synchrotron radiation, and they may be classified into pre-nucleation and nucleation events. X-ray patterns are good indicators for the average behavior of the particles in solution, but they are difficult to interpret unless additional information on their structure is available. We therefore studied the assembly process by electron microscopy under conditions approaching those of the X-ray experiment. There are two difficulties in the EM approach: One is that the particles important for assembly are usually small and not very regular and therefore tend to be overlooked. Secondly EM specimens require low concentrations which favor disassembly of the particles one wants to observe since there is a dynamic equilibrium between polymers and subunits.

Nano-probe x-ray analysis and high-resolution imaging on planar defects in high-pressure synthesized infinite-layer superconductor

1994 ◽  
Vol 52 ◽  
pp. 728-729
Author(s):  
Y. Y. Wang ◽  
H. Zhang ◽  
V. P. Dravid ◽  
H. Zhang ◽  
L. D. Marks ◽  
...  
Keyword(s):  
High Pressure ◽  
High Resolution ◽  
Atomic Structure ◽  
Emission Spectra ◽  
High Resolution Electron Microscopy ◽  
Planar Defects ◽  
X Ray ◽  
Infinite Layer ◽  
Resolution Electron ◽  
Resolution Imaging

Azuma et al. observed planar defects in a high pressure synthesized infinitelayer compound (i.e. ACuO2 (A=cation)), which exhibits superconductivity at ~110 K. It was proposed that the defects are cation deficient and that the superconductivity in this material is related to the planar defects. In this report, we present quantitative analysis of the planar defects utilizing nanometer probe xray microanalysis, high resolution electron microscopy, and image simulation to determine the chemical composition and atomic structure of the planar defects. We propose an atomic structure model for the planar defects.Infinite-layer samples with the nominal chemical formula, (Sr1-xCax)yCuO2 (x=0.3; y=0.9,1.0,1.1), were prepared using solid state synthesized low pressure forms of (Sr1-xCax)CuO2 with additions of CuO or (Sr1-xCax)2CuO3, followed by a high pressure treatment.Quantitative x-ray microanalysis, with a 1 nm probe, was performed using a cold field emission gun TEM (Hitachi HF-2000) equipped with an Oxford Pentafet thin-window x-ray detector. The probe was positioned on the planar defects, which has a 0.74 nm width, and x-ray emission spectra from the defects were compared with those obtained from vicinity regions.

Time-Resolved Cryo-Electron Microscopy of Oscillating Microtubules

1990 ◽  
Vol 48 (1) ◽  
pp. 502-503
Author(s):  
Eva-Maria Mandelkow ◽  
Ron Milligan
Keyword(s):  
Electron Microscopy ◽  
Dynamic Instability ◽  
Entire Solution ◽  
Reaction Scheme ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
A Chain ◽  
Ray Scattering

Microtubules form part of the cytoskeleton of eukaryotic cells. They are hollow libers of about 25 nm diameter made up of 13 protofilaments, each of which consists of a chain of heterodimers of α-and β-tubulin. Microtubules can be assembled in vitro at 37°C in the presence of GTP which is hydrolyzed during the reaction, and they are disassembled at 4°C. In contrast to most other polymers microtubules show the behavior of “dynamic instability”, i.e. they can switch between phases of growth and phases of shrinkage, even at an overall steady state [1]. In certain conditions an entire solution can be synchronized, leading to autonomous oscillations in the degree of assembly which can be observed by X-ray scattering (Fig. 1), light scattering, or electron microscopy [2-5]. In addition such solutions are capable of generating spontaneous spatial patterns [6].In an earlier study we have analyzed the structure of microtubules and their cold-induced disassembly by cryo-EM [7]. One result was that disassembly takes place by loss of protofilament fragments (tubulin oligomers) which fray apart at the microtubule ends. We also looked at microtubule oscillations by time-resolved X-ray scattering and proposed a reaction scheme [4] which involves a cyclic interconversion of tubulin, microtubules, and oligomers (Fig. 2). The present study was undertaken to answer two questions: (a) What is the nature of the oscillations as seen by time-resolved cryo-EM? (b) Do microtubules disassemble by fraying protofilament fragments during oscillations at 37°C?

Self-Consistent Field Calculations of X-Ray Emission Spectra of Surface Adsorbates and Polymers

1997 ◽  
Vol 7 (C2) ◽  
pp. C2-515-C2-516
Author(s):  
H. Agren ◽  
L. G.M. Pettersson ◽  
V. Carravetta ◽  
Y. Luo ◽  
L. Yang ◽  
...  
Keyword(s):  
Emission Spectra ◽  
X Ray ◽  
Consistent Field ◽  
Self Consistent ◽  
Surface Adsorbates ◽  
Self Consistent Field

EXPERIMENTAL AND THEORETICAL SOFT X-RAY EMISSION SPECTRA OF Cu-Pd SUBSTITUTIONAL ALLOYS

1987 ◽  
Vol 48 (C9) ◽  
pp. C9-1059-C9-1062
Author(s):  
P. J. DURHAM ◽  
C. F. HAGUE ◽  
J.-M. MARIOT ◽  
W. M. TEMMERMAN
Keyword(s):  
Emission Spectra ◽  
X Ray ◽  
Substitutional Alloys

Time-resolved X-ray reciprocal space mapping of the crystal under external electric field

2018 ◽  
Vol 189 (02) ◽  
pp. 187-194 ◽  
Author(s):  
Nikita V. Marchenkov ◽  
Anton G. Kulikov ◽  
Ivan I. Atknin ◽  
Arsen A. Petrenko ◽  
Alexander E. Blagov ◽  
...  
Keyword(s):  
Electric Field ◽  
External Electric Field ◽  
Space Mapping ◽  
Reciprocal Space ◽  
Reciprocal Space Mapping ◽  
Time Resolved ◽  
X Ray
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