Publications by Majed Chergui | EPFL Graph Search

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Carbon K-edge resonant Auger spectra of gas-phase allene following excitation of the pre-edge 1s -> pi* transitions are presented and analysed with the support of EOM-CCSD/cc-pVTZ calculations. X-Ray absorption (XAS), X-ray photoelectron (XPS), valence ban ...

The ultrafast vibrational-electronic relaxation upon excitation into the singlet (1)A(2u) (d sigma*-> p sigma) excited state of the d(8)-d(8) binuclear complex Pt-2(P2O5H2)(4) has been investigated in different solvents by femtosecond polychromatic fluorescence up-conversion and femtosecond broadband transient absorption (TA) spectroscopy. Both sets of data exhibit clear signatures of vibrational relaxation and wave packet oscillations of the Pt-Pt stretch vibration in the (1)A(2u) state with a period

X-ray absorption linear dichroism of rutile TiO2 at the Ti K-edge provides information about the electronic states involved in the pre-edge transitions. Here, linear dichroism with high energy resolution is analyzed in combination with ab initio finite dif ...

We present a static and picosecond X-ray absorption study at the Cu K-edge of bis(2,9-dimethyl-1,10-phenanthroline)copper(I) (Cu(dmp)(2); dmp = 2,9-dimethyl-1,10-phenanthroline) dissolved in acetonitrile and dichloromethane. The steady-state photolumi ...

Mol.-dynamics simulations of structural relaxation in electronically excited NO-doped solid neon are presented. The NO impurity is excited to its lowest A (3ss) Rydberg state, inducing a rearrangement of the surrounding medium in the form of a bubble, due to repulsion between the Rydberg electron and the closed-shell surrounding species. The simulations were carried out using the thermal harmonic quantum correction in order to account for quantum effects. The first shell response is characterized by an init

Using ultrafast broad-band transient absorption (TA) spectroscopy of photoexcited MAPbBr3 thin films with probe continua in the visible and the mid- to deep-ultraviolet (UV) ranges, we capture the ultrafast renormalization at the fundamental gap at the R s ...

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 ...

Ultrafast interfacial electron transfer in sensitized solar cells has mostly been probed by visible-to-terahertz radiation, which is sensitive to the free carriers in the conduction band of the semiconductor substrate. Here, we demonstrate the use of deep- ...

The light-induced spin and structure changes upon excitation of the singlet metal-to-ligand charge transfer (1MLCT) state of Fe(II)-polypyridine complexes are investigated in detail in the case of aqueous iron(II)-tris-bipyridine ([FeII(bpy)3]2+) by a combination of ultrafast optical and X-ray spectroscopies. Polychromatic femtosecond fluorescence up-conversion, transient absorption studies in the 290-600nm region and femtosecond X-ray absorption spectroscopy allow us to retrieve the entire photocycle upon

One of the main challenges in ultrafast material science is to trigger phase transitions with short pulses of light. Here we show how strain waves, launched by electronic and structural precursor phenomena, determine a coherent macroscopic transformation p ...

The ion-pair state emission spectra of I2 isolated in Ne, Ar, and Kr matrixes at 300-700 nm and vacuum UV spectra at 50,000-60,000 cm-1 are presented. Spectroscopic anal. of the UV and visible emission bands of the lowest-lying ion-pair state D'(2g) in Ne and Ar provides unambiguous evidence for both vertical (energy) and horizontal shifts (equil. distance) due to solvation in a rare gas matrix, and suggests that the ion-pair states maintain their distinct character. In Kr the previously reported broad emis

The frequency shifts from gas-phase values of the vibrational and rotational states of H2, D2, and HD mols. matrix isolated in solid Ar, Kr, and Xe were calcd. at zero temp. and at pressures 0 ? P ? 570 kbar. Also calcd. were the impurity local mode frequencies vs. pressure. The pure vibrational and rotational-vibrational transitions are strongly red shifted in the solid P = 0, compared to the gas-phase values. This shift is greatest for Xe and smallest for Ar host lattices. The agreement with Raman scatter

Hybrid DFT/classical molecular dynamics of the long-lived triplet excited state of [Ru(bpy)3]2+ (bpy=2,2-bipyridine) in aqueous solution is used to investigate the solvent-mediated electron localization and dynamics in the triplet metal-to-ligand charge-tr ...

Most chemical and biochemical reactions in nature and in industrial processes are driven by thermal effects that bring the reactants above the energy barrier for reaction. In aqueous solutions, this process can also be triggered by the laser driven tempera ...

The advent of x-ray free electron lasers offers new opportunities for x-ray scattering (XRS) studies of ultrafast molecular dynamics in liquids, which have so far been limited to the 100 ps resolution of synchrotrons. In particular, anisotropic XRS induced ...

The ultrafast dynamics of electronic bubble formation upon excitation of the A(3ss) Rydberg state of NO trapped in solid H2 and D2 was studied by femtosecond pump-probe spectroscopy. The evolution of the spherical bubble is followed in real time by a probe pulse, which maps the transient configurations via transitions to higher-lying Rydberg states. Bubble formation is a 1-way process and no oscillations of the bubble are obsd. In addn., thermalization of the system occurs on the time scale of bubble format

Data repository for the following publication: A. Duque-Prata*, H.-Y. Chen*, L. Müller, M. Oppermann, M. Puppin, C. Serpa, C. Bostedt and M. Chergui, “Ultrafast deep-ultraviolet study of photoexcited aqueous Ferrioxalate”, submitted to ChemPhotoCh ...

Bistability in transition-metal complexes can originate from several phenomena, including mixed valence (MV), spincrossover (SCO), and valence tautomerism (VT). In the latter case, valence-tautomeric interconversion (VTI) generates pairs of switchable redox isomers whose physical properties can be controlled by external stimuli, such as light, temperature, and pressure, making these systems promising candidates for molecular devices, spintronics, and chemosensing. Although several strategies exist to modula

Time-integrated fluorescence expts. on native bacteriorhodopsin and on its non-isomerizing form bR5.12 are reported. The exptl. set-up was designed such as to observe emission exclusively from the excited state intermediate I-460. We obtain the first systematic investigation of the fluorescence spectra as a function of the excitation wavelength tuned throughout the entire absorption band of bR. An important finding is that the position of the fluorescence max. does not show a systematic shift when the excit

Using femtosecond-resolved photoluminescence up-conversion, we report the observation of the fluorescence of the high-lying ligand-centered (LC) electronic state upon 266 nm excitation of an iridium complex, Ir(ppy)(3), with a lifetime of 70 +/- 10 fs. It ...

Majed Chergui

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Jahn-Teller effects in initial and final states: high-resolution X-ray absorption, photoelectron and Auger spectroscopy of allene

Vibrational Relaxation and Intersystem Crossing of Binuclear Metal Complexes in Solution

X-ray absorption linear dichroism at the Ti K-edge of rutile (001) TiO2 single crystal

Solvent Induced Luminescence Quenching: Static and Time-Resolved X-Ray Absorption Spectroscopy of a Copper(I) Phenanthroline Complex

Ultrafast structural dynamics in electronically excited solid neon. II. Molecular-dynamics simulations of the electronic bubble formation

Band Gap Renormalization at Different Symmetry Points in Perovskites

A wavelet analysis for the X-ray absorption spectra of molecules

Interfacial Electron Injection Probed by a Substrate-Specific Excitonic Signature

Light-induced spin crossover in Fe(II)-based complexes: The full photocycle unraveled by ultrafast optical and X-ray spectroscopies

Strain wave pathway to semiconductor-to-metal transition revealed by time-resolved X-ray powder diffraction

Solvation of ion-pair states in nonpolar media: I2 in solid neon, argon and krypton

Vibrational and rotational frequency shifts of dilute molecular hydrogen, molecular deuterium, and hydrogen deuteride impurities in solid argon, krypton, and xenon under pressure

Electron Localization Dynamics in the Triplet Excited State of Ru(bpy)3]2+ in Aqueous Solution

Toward time-resolved laser T-jump/X-ray probe spectroscopy in aqueous solutions

Ultrafast anisotropic x-ray scattering in the condensed phase

Structural dynamics in quantum solids. II. Real-time probing of the electronic bubble formation in solid hydrogens

Data for "Ultrafast deep-ultraviolet study of photoexcited aqueous Ferrioxalate"

Uncovering Correlations between Structure and Valence Tautomerism in Cobalt-o-Dioxolene Crystals

Ultrafast energy relaxation in bacteriorhodopsin studied by time-integrated fluorescence

Ligand-Centred Fluorescence and Electronic Relaxation Cascade at Vibrational Time Scales in Transition-Metal Complexes