scholarly journals Probing spin–vibronic dynamics using femtosecond X-ray spectroscopy

2016 ◽  
Vol 194 ◽  
pp. 731-746 ◽  
Author(s):  
T. J. Penfold ◽  
M. Pápai ◽  
T. Rozgonyi ◽  
K. B. Møller ◽  
G. Vankó
Keyword(s):  
Excited State ◽  
Degrees Of Freedom ◽  
Free Electrons ◽  
Edge Structure ◽  
Pump Probe ◽  
X Ray ◽  
Wavepacket Dynamics ◽  
Methyl Imidazole ◽  
Probe Spectroscopy ◽  
X Ray Absorption

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.

Antivitamins B12 in a Microdrop: The Excited-State Structure of a Precious Sample Using Transient Polarized X-ray Absorption Near-Edge Structure

2019 ◽  
Vol 10 (18) ◽  
pp. 5484-5489 ◽  
Author(s):  
Nicholas A. Miller ◽  
Lindsay B. Michocki ◽  
Roberto Alonso-Mori ◽  
Alexander Britz ◽  
Aniruddha Deb ◽  
...  
Keyword(s):  
Excited State ◽  
State Structure ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

scholarly journals Ballistic excited state dynamics revealed by polarized fs-XANES

2019 ◽  
Vol 205 ◽  
pp. 05014 ◽  
Author(s):  
Roseanne J. Sension ◽  
Nicholas A. Miller ◽  
Aniruddha Deb ◽  
Roberto Alonso-Mori ◽  
James M. Glownia ◽  
...  
Keyword(s):  
Excited State ◽  
Time Resolved ◽  
Edge Structure ◽  
X Ray ◽  
Excited State Dynamics ◽  
X Ray Absorption

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.

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.

Beyond structure: ultrafast X-ray absorption spectroscopy as a probe of non-adiabatic wavepacket dynamics

2016 ◽  
Vol 194 ◽  
pp. 117-145 ◽  
Author(s):  
Simon P. Neville ◽  
Vitali Averbukh ◽  
Serguei Patchkovskii ◽  
Marco Ruberti ◽  
Renjie Yun ◽  
...  
Keyword(s):  
Absorption Spectrum ◽  
Excited State ◽  
Absorption Spectroscopy ◽  
Vacuum Ultraviolet ◽  
Chemical Shifts ◽  
Structural Evolution ◽  
Time Resolved ◽  
X Ray ◽  
Wavepacket Dynamics ◽  
X Ray Absorption

The excited state non-adiabatic dynamics of polyatomic molecules, leading to the coupling of structural and electronic dynamics, is a fundamentally important yet challenging problem for both experiment and theory. Ongoing developments in ultrafast extreme vacuum ultraviolet (XUV) and soft X-ray sources present new probes of coupled electronic-structural dynamics because of their novel and desirable characteristics. As one example, inner-shell spectroscopy offers localized, atom-specific probes of evolving electronic structure and bonding (via chemical shifts). In this work, we present the first on-the-fly ultrafast X-ray time-resolved absorption spectrum simulations of excited state wavepacket dynamics: photo-excited ethylene. This was achieved by coupling the ab initio multiple spawning (AIMS) method, employing on-the-fly dynamics simulations, with high-level algebraic diagrammatic construction (ADC) X-ray absorption cross-section calculations. Using the excited state dynamics of ethylene as a test case, we assessed the ability of X-ray absorption spectroscopy to project out the electronic character of complex wavepacket dynamics, and evaluated the sensitivity of the calculated spectra to large amplitude nuclear motion. In particular, we demonstrate the pronounced sensitivity of the pre-edge region of the X-ray absorption spectrum to the electronic and structural evolution of the excited-state wavepacket. We conclude that ultrafast time-resolved X-ray absorption spectroscopy may become a powerful tool in the interrogation of excited state non-adiabatic molecular dynamics.

scholarly journals Ballistic ΔS=2 Intersystem Crossing in a Cobalt Cubane Following Ligand-Field Excitation Probed by Extreme Ultraviolet Spectroscopy

2021 ◽  
Author(s):  
Yusef Shari'ati ◽  
Josh Vura-Weis
Keyword(s):  
Excited State ◽  
Extreme Ultraviolet ◽  
Xanes Spectroscopy ◽  
Ligand Field ◽  
Ultraviolet Spectroscopy ◽  
Intersystem Crossing ◽  
Edge Structure ◽  
X Ray ◽  
Field Excitation ◽  
X Ray Absorption

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...

scholarly journals Ballistic ΔS=2 Intersystem Crossing in a Cobalt Cubane Following Ligand-Field Excitation Probed by Extreme Ultraviolet Spectroscopy

2021 ◽  
Author(s):  
Yusef Shari'ati ◽  
Josh Vura-Weis
Keyword(s):  
Excited State ◽  
Water Oxidation ◽  
Extreme Ultraviolet ◽  
Ligand Field ◽  
Ultraviolet Spectroscopy ◽  
Intersystem Crossing ◽  
Edge Structure ◽  
X Ray ◽  
Field Excitation ◽  
X Ray Absorption

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.

scholarly journals Advanced calculations of X-ray spectroscopies with FEFF10 and Corvus

2021 ◽  
Vol 28 (6) ◽  
Author(s):  
J. J. Kas ◽  
F. D. Vila ◽  
C. D. Pemmaraju ◽  
T. S. Tan ◽  
J. J. Rehr
Keyword(s):  
Real Space ◽  
Vibrational Properties ◽  
Many Body ◽  
Edge Structure ◽  
Pump Probe ◽  
X Ray ◽  
X Ray Scattering ◽  
Function Code ◽  
Electron Energy Loss ◽  
X Ray Absorption

The real-space Green's function code FEFF has been extensively developed and used for calculations of X-ray and related spectra, including X-ray absorption (XAS), X-ray emission (XES), inelastic X-ray scattering, and electron energy-loss spectra. The code is particularly useful for the analysis and interpretation of the XAS fine-structure (EXAFS) and the near-edge structure (XANES) in materials throughout the periodic table. Nevertheless, many applications, such as non-equilibrium systems, and the analysis of ultra-fast pump–probe experiments, require extensions of the code including finite-temperature and auxiliary calculations of structure and vibrational properties. To enable these extensions, we have developed in tandem a new version FEFF10 and new FEFF-based workflows for the Corvus workflow manager, which allow users to easily augment the capabilities of FEFF10 via auxiliary codes. This coupling facilitates simplified input and automated calculations of spectra based on advanced theoretical techniques. The approach is illustrated with examples of high-temperature behavior, vibrational properties, many-body excitations in XAS, super-heavy materials, and fits of calculated spectra to experiment.

Ultrafast nonadiabatic dynamics probed by nitrogen K-edge absorption spectroscopy

2020 ◽  
Vol 22 (5) ◽  
pp. 2667-2676 ◽  
Author(s):  
T. Northey ◽  
J. Norell ◽  
A. E. A. Fouda ◽  
N. A. Besley ◽  
M. Odelius ◽  
...  
Keyword(s):  
Excited States ◽  
Quantum Dynamics ◽  
Degrees Of Freedom ◽  
Nonadiabatic Dynamics ◽  
Edge Structure ◽  
Strongly Coupled ◽  
X Ray ◽  
Electronically Excited ◽  
Dynamics Simulations ◽  
X Ray Absorption

Quantum dynamics simulations are used to simulate the ultrafast X-ray Absorption Near-Edge Structure (XANES) spectra of photoexcited pyrazine including two strongly coupled electronically excited states and four normal mode degrees of freedom.

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 ◽  
...  
Keyword(s):  
Excited State ◽  
Structural Dynamics ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

Chemical and orientational imaging of polymeric samples

1994 ◽  
Vol 52 ◽  
pp. 68-69
Author(s):  
H. Ade ◽  
B. Hsiao ◽  
G. Mitchell ◽  
E. Rightor ◽  
A. P. Smith ◽  
...  
Keyword(s):  
Ethylene Terephthalate ◽  
National Laboratory ◽  
Brookhaven National Laboratory ◽  
Carbonyl Groups ◽  
Aromatic Rings ◽  
Edge Structure ◽  
X Ray ◽  
Scanning Transmission ◽  
Polymeric Samples ◽  
X Ray Absorption

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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