scholarly journals Ultrafast X-ray Absorption Near Edge Structure Reveals Ballistic Excited State Structural Dynamics

2018 ◽  
Vol 122 (22) ◽  
pp. 4963-4971 ◽  
Author(s):  
Nicholas A. Miller ◽  
Aniruddha Deb ◽  
Roberto Alonso-Mori ◽  
James M. Glownia ◽  
Laura M. Kiefer ◽  
...  
2019 ◽  
Vol 10 (18) ◽  
pp. 5484-5489 ◽  
Author(s):  
Nicholas A. Miller ◽  
Lindsay B. Michocki ◽  
Roberto Alonso-Mori ◽  
Alexander Britz ◽  
Aniruddha Deb ◽  
...  

2019 ◽  
Vol 205 ◽  
pp. 05014 ◽  
Author(s):  
Roseanne J. Sension ◽  
Nicholas A. Miller ◽  
Aniruddha Deb ◽  
Roberto Alonso-Mori ◽  
James M. Glownia ◽  
...  

Polarized time-resolved X-ray absorption near edge structure (XANES) is used to characterize the sequential ballistic excited state dynamics of two B12 vitamers: cyanocobalamin and adenosylcobalamin. Excitation at 550 nm and 365 nm is used to resolve axial and equatorial contributions to the excited state dynamics.


Author(s):  
Matthew R. Ross ◽  
Benjamin E Van Kuiken ◽  
Matthew L. Strader ◽  
Hana Cho ◽  
Amy Cordones-Hahn ◽  
...  

Author(s):  
Majed Chergui

The need to visualize molecular structure in the course of a chemical reaction, a phase transformation or a biological function has been a dream of scientists for decades. The development of time-resolved X-ray and electron-based methods is making this true. X-ray absorption spectroscopy is ideal for the study of structural dynamics in liquids, because it can be implemented in amorphous media. Furthermore, it is chemically selective. Using X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) in laser pump/X-ray probe experiments allows the retrieval of the local geometric structure of the system under study, but also the underlying photoinduced electronic structure changes that drive the structural dynamics. Recent developments in picosecond and femtosecond X-ray absorption spectroscopy applied to molecular systems in solution are reviewed: examples on ultrafast photoinduced processes such as intramolecular electron transfer, low-to-high spin change, and bond formation are presented.


2016 ◽  
Vol 145 (14) ◽  
pp. 144307 ◽  
Author(s):  
Simon P. Neville ◽  
Vitali Averbukh ◽  
Marco Ruberti ◽  
Renjie Yun ◽  
Serguei Patchkovskii ◽  
...  

Author(s):  
Yusef Shari'ati ◽  
Josh Vura-Weis

Femtosecond M2,3-edge X-ray absorption near-edge structure (XANES) spectroscopy is used to probe the excited-state dynamics of the cobalt cubane [CoIII4O4](OAc)4(py)4 (OAc = acetate, py = pyridine), a model for water...


2021 ◽  
Author(s):  
Yusef Shari'ati ◽  
Josh Vura-Weis

Femtosecond M2,3-edge X-ray absorption near-edge structure (XANES) spectroscopy is used to probe the excited-state dynamics of the cobalt cubane [CoIII4O4](OAc)4(py)4 (OAc = acetate, py = pyridine), a model for water oxidation catalysts. After ligand-field excitation, intersystem crossing to a metal-centered quintet occurs in 38 fs. 30% of the hot quintet undergoes ballistic back-ISC directly to the singlet ground stat, with the remainder relaxing to a long-lived triplet.


Author(s):  
Matthew Ross ◽  
Benjamin E. Van Kuiken ◽  
Mathew L. Strader ◽  
Amy Cordones-Hahn ◽  
Hana Cho ◽  
...  

2016 ◽  
Vol 194 ◽  
pp. 731-746 ◽  
Author(s):  
T. J. Penfold ◽  
M. Pápai ◽  
T. Rozgonyi ◽  
K. B. Møller ◽  
G. Vankó

Ultrafast pump-probe spectroscopy within the X-ray regime is now possible owing to the development of X-ray Free Electrons Lasers (X-FELs) and is opening new opportunities for the direct probing of femtosecond evolution of the nuclei, the electronic and spin degrees of freedom. In this contribution we use wavepacket dynamics of the photoexcited decay of a new Fe(ii) complex, [Fe(bmip)2]2+ (bmip = 2,6-bis(3-methyl-imidazole-1-ylidine)pyridine), to simulate the experimental observables associated with femtosecond Fe K-edge X-ray Absorption Near-Edge Structure (XANES) and X-ray emission (XES) spectroscopy. We show how the evolution of the nuclear wavepacket is translated into the spectroscopic signal and the sensitivity of these approaches for following excited state dynamics.


Author(s):  
H. Ade ◽  
B. Hsiao ◽  
G. Mitchell ◽  
E. Rightor ◽  
A. P. Smith ◽  
...  

We have used the Scanning Transmission X-ray Microscope at beamline X1A (X1-STXM) at Brookhaven National Laboratory (BNL) to acquire high resolution, chemical and orientation sensitive images of polymeric samples as well as point spectra from 0.1 μm areas. This sensitivity is achieved by exploiting the X-ray Absorption Near Edge Structure (XANES) of the carbon K edge. One of the most illustrative example of the chemical sensitivity achievable is provided by images of a polycarbonate/pol(ethylene terephthalate) (70/30 PC/PET) blend. Contrast reversal at high overall contrast is observed between images acquired at 285.36 and 285.69 eV (Fig. 1). Contrast in these images is achieved by exploring subtle differences between resonances associated with the π bonds (sp hybridization) of the aromatic groups of each polymer. PET has a split peak associated with these aromatic groups, due to the proximity of its carbonyl groups to its aromatic rings, whereas PC has only a single peak.


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