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 (τ650ps) 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±0.008Å).

1.
C.
Bressler
and
M.
Chergui
,
Chem. Rev. (Washington, D.C.)
104
,
1781
(
2004
).
2.
L. X.
Chen
,
Angew. Chem., Int. Ed.
43
,
2886
(
2004
).
M.
Bargheer
,
N.
Zhavoronkov
,
M.
Woerner
, and
T.
Elsaesser
,
ChemPhysChem
7
,
783
(
2006
);
[PubMed]
M.
Chergui
and
A. H.
Zewail
,
ChemPhysChem
10
,
28
(
2009
).
[PubMed]
4.
C.
Bressler
,
R.
Abela
, and
M.
Chergui
,
Z. Kristallogr.
223
,
307
(
2008
).
5.
M.
Khalil
,
M. A.
Marcus
,
A. L.
Smeigh
,
J. K.
McCusker
,
H. H. W.
Chong
, and
R. W.
Schoenlein
,
J. Phys. Chem. A
110
,
38
(
2006
).
6.
R. W.
Schoenlein
,
S.
Chattopadhyay
,
H. H. W.
Chong
,
T. E.
Glover
,
P. A.
Heimann
,
W. P.
Leemans
,
C. V.
Shank
,
A.
Zholents
, and
M.
Zolotorev
,
Appl. Phys. B: Lasers Opt.
71
,
1
(
2000
);
S.
Khan
,
K.
Holldack
,
T.
Kachel
,
R.
Mitzner
, and
T.
Quast
,
Phys. Rev. Lett.
97
,
074801
(
2006
);
[PubMed]
P.
Beaud
,
S. L.
Johnson
,
A.
Streun
,
R.
Abela
,
D.
Abramsohn
,
D.
Grolimund
,
F.
Krasniqi
,
T.
Schmidt
,
V.
Schlott
, and
G.
Ingold
,
Phys. Rev. Lett.
99
,
174801
(
2007
).
[PubMed]
7.
C.
Bressler
,
C. J.
Milne
,
V. T.
Pham
,
A.
Al Nahhas
,
R. M.
van der Veen
,
W.
Gawelda
,
S.
Johnson
,
P.
Beaud
,
D.
Grolimund
,
M.
Kaiser
,
C. N.
Borca
,
G.
Ingold
,
R.
Abela
, and
M.
Chergui
,
Science
323
,
489
(
2009
).
8.
A. H.
Zewail
,
Angew. Chem., Int. Ed.
39
,
2587
(
2000
).
9.
M.
Saes
,
C.
Bressler
,
F.
van Mourik
,
W.
Gawelda
,
M.
Kaiser
,
M.
Chergui
,
C.
Bressler
,
D.
Grolimund
,
R.
Abela
,
T. E.
Glover
,
P. A.
Heimann
,
R. W.
Schoenlein
,
S. L.
Johnson
,
A. M.
Lindenberg
, and
R. W.
Falcone
,
Rev. Sci. Instrum.
75
,
24
(
2004
).
10.
M.
Saes
,
W.
Gawelda
,
M.
Kaiser
,
A.
Tarnovsky
,
C.
Bressler
,
M.
Chergui
,
S. L.
Johnson
,
D.
Grolimund
, and
R.
Abela
,
Synchrotron Radiat. News
16
,
12
(
2003
).
11.
M.
Saes
,
C.
Bressler
,
R.
Abela
,
D.
Grolimund
,
S. L.
Johnson
,
P. A.
Heimann
, and
M.
Chergui
,
Phys. Rev. Lett.
90
,
047403
(
2003
).
12.
W.
Gawelda
,
M.
Johnson
,
F. M. F.
de Groot
,
R.
Abela
,
C.
Bressler
, and
M.
Chergui
,
J. Am. Chem. Soc.
128
,
5001
(
2006
).
13.
W.
Gawelda
,
V. T.
Pham
,
M.
Benfatto
,
Y.
Zaushytsin
,
M.
Kaiser
,
D.
Grolimund
,
S.
Johnson
,
R.
Abela
,
C.
Bressler
, and
M.
Chergui
,
Phys. Rev. Lett.
98
,
057401
(
2007
).
14.
V. T.
Pham
,
W.
Gawelda
,
Y.
Zaushytsin
,
M.
Kaiser
,
D.
Grolimund
,
S.
Johnson
,
R.
Abela
,
C.
Bressler
, and
M.
Chergui
,
J. Am. Chem. Soc.
129
,
1530
(
2007
).
15.
R. F.
Pettifer
,
O.
Mathon
,
S.
Pascarelli
,
M. D.
Cooke
, and
M. R. J.
Gibbs
,
Nature (London)
435
,
78
(
2005
).
16.
W.
Gawelda
, “Time-resolved x-ray absorption spectroscopy of transition metal complexes,” Ph.D. Thesis, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland,
2006
.
17.
C.
Consani
,
M.
Prémont-Schwarz
,
A.
El Nahhas
,
C.
Bressler
,
F.
van Mourik
,
A.
Cannizzo
, and
M.
Chergui
, “Femtosecond UV probe spectroscopy of light-induced spin cross-over in aqueous [FeII(bpy)3]2+,”
J. Am. Chem. Soc.
(submitted).
18.
A. L.
Ankudinov
,
B.
Ravel
,
J. J.
Rehr
, and
S. D.
Conradson
,
Phys. Rev. B
58
,
7565
(
1998
).
20.
S.
Dick
,
Z. Kristallogr.-New Cryst. Struct.
213
,
356
(
1998
).
21.
W.
Gawelda
,
V. T.
Pham
,
A.
El Nahhas
,
M.
Kaiser
,
Y.
Zaushytsin
,
S.
Johnson
,
D.
Grolimund
,
R.
Abela
,
A.
Hauser
,
C.
Bressler
, and
M.
Chergui
,
AIP Conf. Proc.
882
,
31
(
2007
).
22.
P.
Guionneau
,
J. F.
Letard
,
D. S.
Yufit
,
D.
Chasseau
,
G.
Bravic
,
A. E.
Goeta
,
J. A. K.
Howard
, and
O.
Kahn
,
J. Mater. Chem.
9
,
985
(
1999
).
23.
P.
Guionneau
,
M.
Marchivie
,
G.
Bravic
,
J. F.
Letard
, and
D.
Chasseau
,
Top. Curr. Chem.
234
,
97
(
2004
).
24.
L. M.
Lawson Daku
,
A.
Vargas
,
A.
Hauser
,
A.
Fouqueau
, and
M. E.
Casida
,
ChemPhysChem
6
,
1393
(
2005
).
25.
K. B.
Wiberg
,
P. R.
Rablen
,
D. J.
Rush
, and
T. A.
Keith
,
J. Am. Chem. Soc.
117
,
4261
(
1995
).
26.
W.
Gawelda
,
A.
Cannizzo
,
V. T.
Pham
,
F.
van Mourik
,
C.
Bressler
, and
M.
Chergui
,
J. Am. Chem. Soc.
129
,
8199
(
2007
).
27.
B.
Ravel
and
M.
Newville
,
J. Synchrotron Radiat.
12
,
537
(
2005
).
28.
B. D.
Shrivastava
,
B. D.
Shrivastava
,
S. K.
Joshi
,
K. B.
Pandey
, and
A.
Mishra
,
J. Synchrotron Radiat.
8
,
713
(
2001
).
29.
A. N.
Mansour
and
C. A.
Melendres
,
J. Phys. Chem. A
102
,
65
(
1998
).
30.
F. M. F.
de Groot
,
Z. W.
Hu
,
M. F.
Lopez
,
G.
Kaindl
,
F.
Guillot
, and
M.
Tronc
,
J. Chem. Phys.
101
,
6570
(
1994
).
32.
K.
Shimizu
,
H.
Maeshima
,
H.
Yoshida
,
A.
Satsuma
, and
T.
Hattori
,
Phys. Chem. Chem. Phys.
3
,
862
(
2001
).
33.
F. M. F.
de Groot
,
Coord. Chem. Rev.
249
,
31
(
2005
).
34.
R. M.
van der Veen
,
C. J.
Milne
,
J.
Best
,
J. A.
Weinstein
,
A.
El Nahhas
,
V. T.
Pham
,
F.
Lima
,
C.
Bressler
, and
M.
Chergui
,
Angew. Chem., Int. Ed.
40
,
2711
(
2009
).
You do not currently have access to this content.