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Majed Chergui

Cette personne a quitté l’EPFL

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Publications associées (243)

Page 5 sur 13

Aqueous Solvation Dynamics at Metal Oxide Surfaces

Majed Chergui, Jacques-Edouard Moser, Frank van Mourik, Erwin Portuondo Campa

Broadband transient absorption (TA) spectroscopy, three-pulse photon echo peak shift (3PEPS), and anisotropy decay measurements were used to study the solvation dynamics in bulk water and interfacial water at ZrO2 surfaces, using Eosin Y as a probe. The 3P ...

2006

Structural Determination of a Short-Lived Excited Iron(II) Complex by Picosecond X-Ray Absorption Spectroscopy

Majed Chergui, Wojciech Gawelda, Van Thai Pham

Structural changes of the Fe(II)-tris-bipyridine ([FeII(bpy)3]2+) complex induced by ultrashort pulse excitation and population of its short-lived (?0.6 ns) quintet high spin state were detected by picosecond x-ray absorption spectroscopy. The structural r ...

2007

Mahan excitons in room-temperature methylammonium lead bromide perovskites

Majed Chergui, László Forró, Endre Horvath, Ana Akrap, Edoardo Baldini, Márton Kollár, Tania Palmieri

In a seminal paper, Mahan predicted that excitonic bound states can still exist in a semiconductor at electron-hole densities above the insulator-to-metal Mott transition. However, no clear evidence for this exotic quasiparticle, dubbed Mahan exciton, exis ...

Nature Publishing Group2020

Retrieving photochemically active structures by time-resolved EXAFS spectroscopy

Majed Chergui, Wojciech Gawelda, Van Thai Pham, Amal El Nahhas, Renske Marjan van der Veen, Frederico Alves Lima

Describing the nature and structure of molecular excited states is important in order to understand their chemical reactivity and role as intermediates in photochemical reactions. The recent implementation of x-ray absorption spectroscopy in the ultrafast ...

Iop Publishing Ltd, Dirac House, Temple Back, Bristol Bs1 6Be, England2009

Photoaquation Mechanism of Hexacyanoferrate(II) Ions: Ultrafast 2D UV and Transient Visible and IR Spectroscopies

Majed Chergui, Thomas James Penfold, Gerald Auböck, Marco Eli Reinhard

Ferrous iron(II) hexacyanide in aqueous solutions is known to undergo photoionization and photoaquation reactions depending on the excitation wavelength. To investigate this wavelength dependence, we implemented ultrafast two-dimensional UV transient absor ...

American Chemical Society2017

Towards X-ray transient grating spectroscopy

Patrice Beaud, Majed Chergui, Giulia Fulvia Mancini, Jérémy Raymond Jean Maurice Rouxel, Erwan Fabrice Koch

The extension of transient grating spectroscopy to the x-ray regime will create numerous opportunities, ranging from the study of thermal transport in the ballistic regime to charge, spin, and energy transfer processes with atomic spatial and femtosecond t ...

OPTICAL SOC AMER2019

Vibrational coherences and relaxation in the high-spin state of aqueous [Fell(bpy)3]2+

Majed Chergui, Frank van Mourik, Andrea Cannizzo, Amal El Nahhas, Cristina Consani

Dizzy cooling: Femtosecond excitation of the singlet states of aqueous [FeII(bpy)3]2+ (bpy=2,2-bipyridine) leads to the formation of a vibrationally hot quintet state that exhibits wave-packet dynamics arising from a chelate-ring and bending mode. The vibr ...

Wiley-VCH Verlag GmbH2009

Insights into excited-state and isomerization dynamics of bacteriorhodopsin from ultrafast transient UV absorption

Majed Chergui, Frank van Mourik, Selma Schenkl

A visible-pump/UV-probe transient absorption is used to characterize the ultrafast dynamics of bacteriorhodopsin with 80-fs time resoln. We identify three spectral components in the 265- to 310-nm region, related to the all-trans retinal, tryptophan (Trp)- ...

National Academy of Sciences2006

Femtosecond carrier dynamics in bulk graphite and graphene paper

Majed Chergui, Fabrizio Carbone, Frank van Mourik, Andrea Cannizzo, Gerald Auböck

Femtosecond white-light continuum probe transient absorption and reflectivity measurements of bulk graphite and graphene paper are reported. In graphite, the relaxation of photoinduced electron–hole pairs happens through in-plane electron–electron and elec ...

Elsevier2011

Picosecond and femtosecond X-ray absorption spectroscopy of molecular systems

Majed Chergui

The need to visualize molecular structure in the course of a chemical reaction, a phase transformation or a biological function has been a dream of scientists for decades. The development of time-resolved X-ray and electron-based methods is making this tru ...

2010

Probing the Transition from Hydrophilic to Hydrophobic Solvation with Atomic Scale Resolution

Majed Chergui, Ivano Tavernelli, Van Thai Pham, Thomas James Penfold, Amal El Nahhas, Renske Marjan van der Veen, Frederico Alves Lima

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,L-3 edge EXAFS at 50 ps time delay points to ...

2011

Nanoscale-Resolved Surface-to-Bulk Electron Transport in CsPbBr3 Perovskite

Majed Chergui, Nicola Marzari, Marco Grioni, Alberto Crepaldi, Michele Puppin, Nicola Colonna, Gianmarco Gatti, Serhii Polishchuk

Describing the nanoscale charge carrier transport at surfaces and interfaces is fundamental for designing highperformance optoelectronic devices. To achieve this, we employ time-and angle-resolved photoelectron spectroscopy with ultraviolet pump and extrem ...

AMER CHEMICAL SOC2022

Ultrafast inter-ionic charge transfer of transition-metal complexes mapped by femtosecond X-ray powder diffraction

Majed Chergui

The transient electronic and molecular structure arising from photoinduced charge transfer in transition metal complexes is studied by X-ray powder diffraction with a 100 fs temporal and atomic spatial resolution. Crystals containing a dense array of Fe(II ...

American Institute of Physics2013

Ultrafast electronic and vibrational relaxations in mixed-ligand dithione-dithiolato Ni, Pd, and Pt complexes

Majed Chergui, Frank van Mourik, Andrea Cannizzo, Ahmad Odeh

Ultrafast excited-state dynamics of planar Pt, Pd, and Ni dithione-dithiolato complexes were investigated by transient absorption spectroscopy on the femtosecond-picosecond timescale. All studied complexes show a common photobehaviour, although individual ...

Royal Society of Chemistry2014

Broad-Band Ultraviolet CD Spectroscopy of Ultrafast Peptide Backbone Conformational Dynamics

Majed Chergui, Malte Oppermann, Benjamin Bauer

The far-UV spectral window widely used for the conformational analysis of biomolecules is not easily covered with broad-band lasers. This has made it difficult to use circular dichroism (CD) spectroscopy to directly follow fast structure changes. By combin ...

AMER CHEMICAL SOC2019

The molecular cat

Majed Chergui

A manifestation of electronic entanglement in core-level spectroscopic measurements of diatomic molecules, reported recently by Schoffler and co-workers, is discussed. The results are reminiscent of Schrodinger's famous Gedanken experiment with the cat (se ...

2009

Ultrafast Nonadiabatic Dynamics of [FeII(bpy)3]2+ in Solution

Majed Chergui, Frank van Mourik, Andrea Cannizzo, Wojciech Gawelda, Van Thai Pham

The ultrafast relaxation of aq. Fe(II)-tris(bipyridine) upon excitation into the singlet metal-to-ligand charge-transfer band (1MLCT) was characterized by femtosecond fluorescence up-conversion and transient absorption (TA) studies. The fluorescence expt. ...

2007

Heterogeneity and relaxation dynamics of the photoexcited retianl Schiff base cation in solution

Majed Chergui, Stefan Haacke, Goran Zgrablic

We present steady-state and broadband femtosecond fluorescence spectra of the protonated Schiff base of retinal in various protic and aprotic solvents, as a function of the excitation wavelength. A detailed spectral decomposition of the time-resolved fluor ...

2009

Ahmed Hassan Zewail OBITUARY

Majed Chergui

American Institute of Physics2016

In Memoriam: Ahmed Hassan Zewail (1946-2016)

Majed Chergui

Amer Inst Physics2016