Amal El Nahhas

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Picosecond and femtosecond X-ray absorption spectroscopy is used to probe the changes of the solvent shell structure upon electron abstraction of aqueous iodide using an ultrashort laser pulse. The transient L(1,3) edge EXAFS at 50 ps time delay points to the formation of an expanded water cavity around the iodine atom, in good agreement with classical and(More)
Ultrafast electronic-vibrational relaxation upon excitation of the singlet charge-transfer b (1)A' state of [Re(L)(CO) 3(bpy)] ( n ) (L = Cl, Br, I, n = 0; L = 4-Et-pyridine, n = 1+) in acetonitrile was investigated using the femtosecond fluorescence up-conversion technique with polychromatic detection. In addition, energies, characters, and molecular(More)
Ultrafast X-ray absorption spectroscopy is a powerful tool to observe electronic and geometric structures of short-lived reaction intermediates. The ab initio FEFF9 code is applied to simulate the Pt L(3)-edge XANES spectrum of the photocatalytic diplatinum molecule [Pt(2)(P(2)O(5)H(2))(4)](4-) and the photo-induced changes that occur therein. The spectra(More)
We present a Wavelet transform analysis for the X-ray absorption spectra of molecules. In contrast to the traditionally used Fourier transform approach, this analysis yields a 2D correlation plot in both R- and k-space. As a consequence, it is possible to distinguish between different scattering pathways at the same distance from the absorbing atom and(More)
Steady-state and picosecond time-resolved X-ray absorption spectroscopy is used to study the ground and lowest triplet states of [ReX(CO)(3)(bpy)](n+), X = Etpy (n = 1), Cl, or Br (n = 0). We demonstrate that the transient spectra at both the Re L(3)- and Br K-edges show the emergence of a pre-edge feature, absent in the ground-state spectrum, which is(More)
Femto- to picosecond excited-state dynamics of the complexes [Re(L)(CO)(3)(N,N)](n) (N,N = bpy, phen, 4,7-dimethyl-phen (dmp); L = Cl, n = 0; L = imidazole, n = 1+) were investigated using fluorescence up-conversion, transient absorption in the 650-285 nm range (using broad-band UV probe pulses around 300 nm) and picosecond time-resolved IR (TRIR)(More)
X-ray absorption spectra of fac-[ReBr(CO)3(bpy)] near the Re L3- and Br K-edges were measured in a steady-state mode as well as time-resolved at 630 ps after 355 nm laser pulse excitation. Relativistic spin-orbit time-dependent density functional theory (TD-DFT) calculations account well for the shape of the near-edge absorption (the ″white line″) of the(More)
Ultrafast excited-state dynamics of [Re(L)(CO)(3)(bpy)](n) (L = Cl, Br, n = 0; L = 4-ethyl-pyridine (Etpy), n = 1+; bpy = 2,2'-bipyridine) have been investigated in dimethylformamide (DMF) solution by fluorescence up-conversion (FlUC) and UV-vis transient absorption (TA) with approximately 100 fs time resolution. TA was also measured in the(More)
Metallica: A large contraction of the Pt-Pt bond in the triplet excited state of the photoreactive [Pt(2)(P(2)O(5)H(2))(4)](4-) ion is determined by time-resolved X-ray absorption spectroscopy (see picture). The strengthening of the Pt-Pt interaction is accompanied by a weakening of the ligand coordination bonds, resulting in an elongation of the(More)
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