scholarly journals NO binding kinetics in myoglobin investigated by picosecond Fe K-edge absorption spectroscopy

2015 ◽  
Vol 112 (42) ◽  
pp. 12922-12927 ◽  
Author(s):  
Mahsa Silatani ◽  
Frederico A. Lima ◽  
Thomas J. Penfold ◽  
Jochen Rittmann ◽  
Marco E. Reinhard ◽  
...  
Keyword(s):  
Active Center ◽  
Absorption Spectroscopy ◽  
Spectroscopic Studies ◽  
Pump Probe ◽  
X Ray ◽  
The Difference ◽  
Direct Sensitivity ◽  
X Ray Absorption ◽  
Recombination Kinetics ◽  
532 Nm

Diatomic ligands in hemoproteins and the way they bind to the active center are central to the protein’s function. Using picosecond Fe K-edge X-ray absorption spectroscopy, we probe the NO-heme recombination kinetics with direct sensitivity to the Fe-NO binding after 532-nm photoexcitation of nitrosylmyoglobin (MbNO) in physiological solutions. The transients at 70 and 300 ps are identical, but they deviate from the difference between the static spectra of deoxymyoglobin and MbNO, showing the formation of an intermediate species. We propose the latter to be a six-coordinated domed species that is populated on a timescale of ∼200 ps by recombination with NO ligands. This work shows the feasibility of ultrafast pump–probe X-ray spectroscopic studies of proteins in physiological media, delivering insight into the electronic and geometric structure of the active center.

scholarly journals Pump–probe XAS investigation of the triplet state of an Ir photosensitizer with chromenopyridinone ligands

2018 ◽  
Vol 17 (7) ◽  
pp. 896-902 ◽  
Author(s):  
Grigory Smolentsev ◽  
Kaj M. van Vliet ◽  
Nicolo Azzaroli ◽  
Jeroen A. van Bokhoven ◽  
Albert M. Brouwer ◽  
...  
Keyword(s):  
Excited State ◽  
Dft Calculations ◽  
Triplet State ◽  
Absorption Spectroscopy ◽  
Triplet Excited State ◽  
Pump Probe ◽  
X Ray ◽  
X Ray Absorption

The triplet excited state of a new Ir-based photosensitizer with two chromenopyridinone and one bipyridine-based ligands has been studied by pump–probe X-ray absorption spectroscopy (XANES) coupled with DFT calculations.

Mn K-Edge X-Ray Absorption Spectroscopy (XAS) Studies of La1-xSrxMnO3

1997 ◽  
Vol 494 ◽  
Author(s):  
S. M. Mini ◽  
J. F. Mitchells ◽  
D. G. Hinks ◽  
Ahmet Alatasi ◽  
D. Rosenmann ◽  
...  
Keyword(s):  
Manganese Oxide ◽  
Absorption Spectroscopy ◽  
Energy Shift ◽  
Hole Doping ◽  
Oxide Systems ◽  
X Ray ◽  
Colossal Magnetoresistive ◽  
The Difference ◽  
X Ray Absorption ◽  
Made In

ABSTRACTSystematic Mn K-edge x-ray absorption spectroscopy (XAS) measurements on samples of La1-xSrxMnO3, which are precursors to colossal magnetoresistive (CMR) materials, are reported. Detailed results on the edge or chemical shift as a function of Sr concentration (hole doping) and sample preparation (air vs oxygen annealed), are discussed. For comparison, a systematic XANES study of the Mn K-edge energy shift, denoting valence change in Mn, has been made in standard manganese oxide systems. Contrary to expectations, the variation in near-edge energies for Mn in La0.725Sr0.275MnO3 were small when compared to the difference between that for manganese oxide standards of nominal valence of +3 and +4 (Mn2O3 and MnO2).

scholarly journals Calcite Nanocrystals Investigated Using X-ray Absorption Spectroscopy

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 490
Author(s):  
Varsha Singh ◽  
Anil Kumar Paidi ◽  
Cheol-Hwee Shim ◽  
So Hee Kim ◽  
Sung Ok Won ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Shape Change ◽  
Spectroscopic Studies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Raman Spectroscopic ◽  
Coordination Numbers ◽  
Transmission Electron ◽  
Local Electronic Structure ◽  
X Ray Absorption

For the present work, calcite nanocrystals were grown by annealing precursors at 500 °C. These precursors were obtained by three different thermal schemes. Among these schemes, two involve heating at 100 °C for 16 h and 16 + 24 h, respectively. In the third scheme, heating was performed at 100 °C for 16 h, followed by annealing at 300 °C for 24 h. X-ray diffraction studies, followed by Fourier transform infrared and Raman spectroscopic studies, exhibited the formation of calcite phase of calcium carbonate. Transmission electron microscopy showed that particle sizes of synthesized calcite nanocrystals were in the range of 25–40 nm. Onsets of shape change were also observed with different thermal schemes, using these measurements. X-ray absorption spectroscopy envisaged that the coordination numbers of Ca-O and Ca-Ca shell were not influenced by the thermal schemes; however, bond lengths of these shells were modified. This study in the near edge region evidenced the manifestation of a local electronic structure of calcite when kept in an open environment, depending upon different thermal schemes.

scholarly journals Decomposing electronic and lattice contributions in optical pump-X-ray probe transient inner-shell absorption spectroscopy of CuO

2019 ◽  
Vol 205 ◽  
pp. 04015
Author(s):  
Johannes Mahl ◽  
Stefan Neppl ◽  
Friedrich Roth ◽  
Catherine Saladrigas ◽  
Hendrik Bluhm ◽  
...  
Keyword(s):  
Absorption Spectra ◽  
Absorption Spectroscopy ◽  
Laser Pulses ◽  
Temperature Dependent ◽  
Optical Pump ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Absorption ◽  
532 Nm

Electronic and lattice contributions to transient X-ray absorption spectra of CuO are analyzed using picosecond time-resolved and temperature-dependent measurements. Super-bandgap excitation with 355 nm and 532 nm laser pulses leads to significantly different trends.

scholarly journals Tracking reaction dynamics in solution by pump–probe X-ray absorption spectroscopy and X-ray liquidography (solution scattering)

2016 ◽  
Vol 52 (19) ◽  
pp. 3734-3749 ◽  
Author(s):  
Jeongho Kim ◽  
Kyung Hwan Kim ◽  
Key Young Oang ◽  
Jae Hyuk Lee ◽  
Kiryong Hong ◽  
...  
Keyword(s):  
Real Time ◽  
Absorption Spectroscopy ◽  
Reaction Dynamics ◽  
Solution Phase ◽  
Pump Probe ◽  
X Ray ◽  
Electronic Dynamics ◽  
Photoinduced Reactions ◽  
X Ray Absorption

TRXL and TRXAS are powerful techniques for real-time probing of structural and electronic dynamics of photoinduced reactions in solution phase.

scholarly journals Электронная структура полианилина, модифицированного солями меди и циркония

2020 ◽  
Vol 128 (5) ◽  
pp. 617
Author(s):  
В.А. Шматко ◽  
Т.Н. Мясоедова ◽  
Г.Э. Яловега
Keyword(s):  
Electronic Structure ◽  
Ir Spectroscopy ◽  
Absorption Spectroscopy ◽  
Photoelectron Spectroscopy ◽  
Spectroscopic Studies ◽  
Chemical Bonds ◽  
X Ray ◽  
Chemical States ◽  
X Ray Absorption ◽  
Modifying Additive

The results of spectroscopic studies of the electronic structure and chemical bonds of PANI - Me composites (Me - Cu, Zr) are presented. X-ray absorption spectroscopy, X-ray photoelectron spectroscopy, IR spectroscopy were used for research. It was established that regardless of which modifying additive polyaniline is used in composites is in partially oxidized form, however, in PANI - Zr is more oxidized than in PANI - Cu. The chemical states of nitrogen in the composites are determined; a different ratio of neutral and charged nitrogen groups is observed.

Chemical and structural applications of X-ray absorption spectroscopy in mineralogy

1989 ◽  
Vol 86 ◽  
pp. 1533-1545 ◽  
Author(s):  
A. Manceau ◽  
J.M. Combes ◽  
G. Calas
Keyword(s):  
Absorption Spectroscopy ◽  
X Ray ◽  
Structural Applications ◽  
X Ray Absorption
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