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Structural analysis of ultrafast extended x-ray absorption fine structure with subpicometer spatial resolution : Application to spin crossover complexes

Gawelda, W. ; Van Der Veen, R. M. ; Grolimund, D. ; Abela, R. ; Chergui, M. ; Bressler, C. and Pham, Van-Thai LU (2009) In Journal of Chemical Physics 130(12).
Abstract

We present a novel analysis of time-resolved extended x-ray absorption fine structure (EXAFS) spectra based on the fitting of the experimental transients obtained from optical pump/x-ray probe experiments. We apply it to the analysis of picosecond EXAFS data on aqueous [FeII (bpy)3] 2+, which undergoes a light induced conversion from its low-spin (LS) ground state to the short-lived (τ≈650 ps) excited high-spin (HS) state. A series of EXAFS spectra were simulated for a collection of possible HS structures from which the ground state fit spectrum was subtracted to generate transient difference absorption (TA) spectra. These are then compared with the experimental TA spectrum using a least-squares... (More)

We present a novel analysis of time-resolved extended x-ray absorption fine structure (EXAFS) spectra based on the fitting of the experimental transients obtained from optical pump/x-ray probe experiments. We apply it to the analysis of picosecond EXAFS data on aqueous [FeII (bpy)3] 2+, which undergoes a light induced conversion from its low-spin (LS) ground state to the short-lived (τ≈650 ps) excited high-spin (HS) state. A series of EXAFS spectra were simulated for a collection of possible HS structures from which the ground state fit spectrum was subtracted to generate transient difference absorption (TA) spectra. These are then compared with the experimental TA spectrum using a least-squares statistical analysis to derive the structural change. This approach reduces the number of required parameters by cancellation in the differences. It also delivers a unique solution for both the fractional population and the extracted excited state structure. We thus obtain a value of the Fe-N bond elongation in the HS state with subpicometer precision (0.203±0.008 Å).

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publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Chemical Physics
volume
130
issue
12
article number
124520
publisher
American Institute of Physics (AIP)
external identifiers
  • pmid:19334864
  • scopus:63649148121
ISSN
0021-9606
DOI
10.1063/1.3081884
language
English
LU publication?
no
id
d2256aff-1670-41ca-a1cd-ace595a9c848
date added to LUP
2019-06-30 10:00:19
date last changed
2024-05-14 17:46:45
@article{d2256aff-1670-41ca-a1cd-ace595a9c848,
  abstract     = {{<p>We present a novel analysis of time-resolved extended x-ray absorption fine structure (EXAFS) spectra based on the fitting of the experimental transients obtained from optical pump/x-ray probe experiments. We apply it to the analysis of picosecond EXAFS data on aqueous [Fe<sup>II</sup> (bpy)<sub>3</sub>] <sup>2+</sup>, which undergoes a light induced conversion from its low-spin (LS) ground state to the short-lived (τ≈650 ps) excited high-spin (HS) state. A series of EXAFS spectra were simulated for a collection of possible HS structures from which the ground state fit spectrum was subtracted to generate transient difference absorption (TA) spectra. These are then compared with the experimental TA spectrum using a least-squares statistical analysis to derive the structural change. This approach reduces the number of required parameters by cancellation in the differences. It also delivers a unique solution for both the fractional population and the extracted excited state structure. We thus obtain a value of the Fe-N bond elongation in the HS state with subpicometer precision (0.203±0.008 Å).</p>}},
  author       = {{Gawelda, W. and Van Der Veen, R. M. and Grolimund, D. and Abela, R. and Chergui, M. and Bressler, C. and Pham, Van-Thai}},
  issn         = {{0021-9606}},
  language     = {{eng}},
  month        = {{04}},
  number       = {{12}},
  publisher    = {{American Institute of Physics (AIP)}},
  series       = {{Journal of Chemical Physics}},
  title        = {{Structural analysis of ultrafast extended x-ray absorption fine structure with subpicometer spatial resolution : Application to spin crossover complexes}},
  url          = {{http://dx.doi.org/10.1063/1.3081884}},
  doi          = {{10.1063/1.3081884}},
  volume       = {{130}},
  year         = {{2009}},
}