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Majed Chergui

Cette personne a quitté l’EPFL

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Publications associées (243)

Page 3 sur 13

Giant two-photon absorption of anatase TiO2 in Au/TiO2 core-shell nanoparticles

Majed Chergui, Malte Oppermann, Lijie Wang

We report on deep-to-near-UV transient absorption spectra of core-shell Au/SiO2 and Au/TiO2 nanoparticles (NPs) excited at the surface plasmon resonance of the Au core, and of UV-excited bare anatase TiO2 NPs. The bleaching of the first excitonic transitio ...

CHINESE LASER PRESS2023

Dynamic multiple-scattering treatment of X-ray absorption: Parameterization of a new molecular dynamics force field for myoglobin

Majed Chergui

We present a detailed analysis of the X-ray absorption near-edge structure (XANES) data on the Fe K-edge of CO Myoglobin based on a combined procedure of Molecular Dynamics (MD) calculations and MXAN (Minuit XANes) data analysis that we call D-MXAN. The ab ...

AMER INST PHYSICS2018

Functional electric field changes in photoactivated proteins revealed by ultrafast Stark spectroscopy of the Trp residues

Majed Chergui, Frank van Mourik, Andrea Cannizzo, Erwin Portuondo Campa, Stefan Haacke

Ultrafast transient absorption spectroscopy of wild-type bacteriorhodopsin (WT bR) and 2 tryptophan mutants (W86F and W182F) is performed with visible light excitation (pump) and UV probe. The aim is to investigate the photoinduced change in the charge dis ...

2009

Femtosecond X-ray emission study of the spin cross-over dynamics in haem proteins

Majed Chergui, Giulia Fulvia Mancini, Oliviero Cannelli, Dominik Kinschel, Camila Bacellar Cases Da Silveira, Jérémy Raymond Jean Maurice Rouxel, Boris Sorokin, James Michael Budarz

In haemoglobin the change from the low-spin (LS) hexacoordinated haem to the high spin (HS, S = 2) pentacoordinated domed deoxy-myoglobin (deoxyMb) form upon ligand detachment from the haem and the reverse process upon ligand binding are what ultimately dr ...

Nature Research2020

Time-resolved Element-selective Probing of Charge Carriers in Solar Materials

Majed Chergui, Mercedes Hannelore Rittmann-Frank, Jochen Rittmann, Thomas Charles Henry Rossi, Dominik Kinschel, Fabio Giacomo Santomauro, James Michael Budarz

We review our recent results on the implementation of picosecond (ps) X-ray absorption spectroscopy to probe the electronic and geometric structure of centres formed by photoexcitation of solar materials such as TiO2 polymorphs and inorganic Cs-based perov ...

2017

Photo-induced dynamics of the heme centers in cytochrome bc(1)

Majed Chergui, Frank van Mourik, Andre Al Haddad, Adrien Alexis Paul Chauvet

The ultrafast response of cytochrome bc1 is investigated for the first time, via transient absorption spectroscopy. The distinct redox potentials of both c(1)- and b-hemes allow for a clear differentiation of their respective signals. We find that while th ...

Royal Society of Chemistry2015

Quantifying Photoinduced Polaronic Distortions in Inorganic Lead Halide Perovskite Nanocrystals

Majed Chergui, Giulia Fulvia Mancini, Michele Puppin, Nicola Colonna, Oliviero Cannelli, Andre Al Haddad, Thomas Charles Henry Rossi, Dominik Kinschel, Ludmila Maria Diniz Leroy, James Michael Budarz

The development of next-generation perovskite-based optoelectronic devices relies critically on the understanding of the interaction between charge carriers and the polar lattice in out-of-equilibrium conditions. While it has become increasingly evident fo ...

2021

Evidence of Large Polarons in Photoemission Band Mapping of the Perovskite Semiconductor CsPbBr3

Matthias Wolf, Majed Chergui, Nicola Marzari, Marco Grioni, Alberto Crepaldi, Michele Puppin, Nicola Colonna, Gianmarco Gatti, Serhii Polishchuk, Riccardo De Gennaro, Thomas Roland Barillot

Lead-halide perovskite (LHP) semiconductors are emergent optoelectronic materials with outstanding transport properties which are not yet fully understood. We find signatures of large polaron formation in the electronic structure of the inorganic LHP CsPbB ...

AMER PHYSICAL SOC2020

Charge-transfer and impulsive electronic-to-vibrational energy conversion in ferricyanide: ultrafast photoelectron and transient infrared studies'

Majed Chergui, Christopher Alexander Arrell, José Javier Pancracio Ojeda Andara, Luca Longetti

The photophysics of ferricyanide in H2O, D2O and ethylene glycol was studied upon excitation of ligand-to-metal charge transfer (LMCT) transitions by combining ultrafast photoelectron spectroscopy (PES) of liquids and transient vibrational spectroscopy. Up ...

Royal Society of Chemistry2017

Chiral control of spin-crossover dynamics in Fe (II) complexes

Majed Chergui, Malte Oppermann

Iron-based spin-crossover complexes hold tremendous promise as multifunctional switches in molecular devices. However, real-world technological applications require the excited high-spin state to be kinetically stable-a feature that has been achieved only ...

NATURE PORTFOLIO2022

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

Majed Chergui, Camila Bacellar Cases Da Silveira, Rebecca Ann Ingle, Luca Longetti, Ludmila Maria Diniz Leroy, Thomas Roland Barillot, Daniel Hollas

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 ...

ROYAL SOC CHEMISTRY2023

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

Majed Chergui, Giulia Fulvia Mancini, Thomas Charles Henry Rossi, Camila Bacellar Cases Da Silveira, Dominik Kinschel, Oliviero Cannelli, Jérémy Raymond Jean Maurice Rouxel

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 ...

INT UNION CRYSTALLOGRAPHY2020

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

Ursula Röthlisberger, Majed Chergui, Ivano Tavernelli, Thomas James Penfold, Olivier Christian Bräm, Mercedes Hannelore Rittmann-Frank, Gloria Capano, Frederico Alves Lima, Marco Eli Reinhard, Jochen Rittmann, Lotta Susanne Karlsson

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 ...

Amer Chemical Soc2013

Band Gap Renormalization at Different Symmetry Points in Perovskites

Majed Chergui, Lijie Wang

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 ...

Amer Chemical Soc2024

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

Ursula Röthlisberger, Majed Chergui, Ivano Tavernelli, Thomas James Penfold, Amal El Nahhas, Marco Eli Reinhard

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 ...

American Institute of Physics2013

Interfacial Electron Injection Probed by a Substrate-Specific Excitonic Signature

Majed Chergui, Edoardo Baldini, Enrico Pomarico, Malte Oppermann, Gerald Auböck, Thomas Charles Henry Rossi, Tania Palmieri

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- ...

2017

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

Majed Chergui, Giulia Fulvia Mancini

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 ...

Nature Research2021

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

Ursula Röthlisberger, Majed Chergui, Ivano Tavernelli

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 ...

2010

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

Majed Chergui, Giulia Fulvia Mancini, Oliviero Cannelli, Dominik Kinschel, Camila Bacellar Cases Da Silveira, Benjamin Bauer, Rebecca Ann Ingle

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 ...

2019

Ultrafast anisotropic x-ray scattering in the condensed phase

Ursula Röthlisberger, Majed Chergui, Ivano Tavernelli, Thomas James Penfold

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 ...

Institute of Physics (IoP) and Deutsche Physikalische Gesellschaft2012