Recherche

Afficher tous les résultats pour

Accueil

Personne

Majed Chergui

À propos
Confidentialité
Mentions légales

Graph Chatbot

Publications associées (250)

Tryptophan-to-heme electron transfer in ferrous myoglobins

Majed Chergui, Frank van Mourik, Gerald Auböck, Roberto Monni, Andre Al Haddad

It was recently demonstrated that in ferric myoglobins (Mb) the fluorescence quenching of the photoexcited tryptophan 14 (*Trp(14)) residue is in part due to an electron transfer to the heme porphyrin (porph), turning it to the ferrous state. However, the ...

National Academy of Sciences2015

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

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

Majed Chergui, Mahsa Silatani, Enrico Pomarico

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 ...

Amer Chemical Soc2015

Empirical rules of molecular photophysics in the light of ultrafast spectroscopy

Majed Chergui

The advent of ultrafast laser spectroscopy has allowed entirely new possibilities for the investigation of the ultrafast photophysics of inorganic metal-based molecular complexes. In this review we show different regimes where non-Kasha behavior shows up. ...

International Union of Pure and Applied Chemistry2015

Probing wavepacket dynamics using ultrafast x-ray spectroscopy

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

The advent of x-ray free electron lasers is providing new opportunities for probing the ultrafast excited state dynamics using structurally sensitive techniques. Herein we use excited state wavepacket dynamics of a prototypical Cu(I)-phenanthroline complex ...

IOP Publishing2015

Probing the electronic and geometric structure of ferric and ferrous myoglobins in physiological solutions by Fe K-edge absorption spectroscopy

Majed Chergui, Ursula Röthlisberger, Ivano Tavernelli, Frederico Alves Lima, Marco Eli Reinhard, Thomas James Penfold

We present an iron K-edge X-ray absorption study of carboxymyoglobin (MbCO), nitrosylmyoglobin (MbNO), oxymyoglobin (MbO(2)), cyanomyoglobin (MbCN), aquomet myoglobin (metMb) and unligated myoglobin (deoxyMb) in physiological media. The analysis of the XAN ...

2014

Mapping of the Photoinduced Electron Traps in TiO2 by Picosecond X-ray Absorption Spectroscopy

Majed Chergui, Marco Eli Reinhard, Mercedes Hannelore Rittmann-Frank, Thomas James Penfold, Jochen Rittmann

Titanium dioxide (TiO2) is the most popular material for applications in solar-energy conversion and photocatalysis, both of which rely on the creation, transport, and trapping of charges (holes and electrons). The nature and lifetime of electron traps at ...

Wiley-Blackwell2014

A simple electron time-of-flight spectrometer for ultrafast vacuum ultraviolet photoelectron spectroscopy of liquid solutions

Majed Chergui, Frank van Mourik, Christopher Alexander Arrell, José Javier Pancracio Ojeda Andara

We present a simple electron time of flight spectrometer for time resolved photoelectron spectroscopy of liquid samples using a vacuum ultraviolet (VUV) source produced by high-harmonic generation. The field free spectrometer coupled with the time-preservi ...

Amer Inst Physics2014

Probing the dynamics of plasmon-excited hexanethiol-capped gold nanoparticles by picosecond X-ray absorption spectroscopy

Majed Chergui, Thomas James Penfold, Jochen Rittmann

Picosecond X-ray absorption spectroscopy (XAS) is used to investigate the electronic and structural dynamics initiated by plasmon excitation of 1.8 nm diameter Au nanoparticles (NPs) functionalised with 1-hexanethiol. We show that 100 ps after photoexcitat ...

Royal Society of Chemistry2014

A Quantum Dynamics Study of the Ultrafast Relaxation in a Prototypical Cu(I)-Phenanthroline

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

The ultrafast nonadiabatic dynamics of a prototypical Cu(I)phenanthroline complex, Cu(dmp)(2) (dmp = 2,9-dimethyl-1,10-phenanthroline), initiated after photoexcitation into the optically bright metal-to-ligand charge-transfer (MLCT) state (S-3) is inv ...

2014

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

Recent experimental and theoretical developments in time-resolved X-ray spectroscopies

Majed Chergui, Thomas James Penfold

Capturing the evolving geometric and electronic structure in the course of a chemical reaction or biological process is the principal aim of time-resolved X-ray spectroscopies. Recent technological and methodological improvements, such as high repetition r ...

Elsevier2014

Emerging photon technologies for chemical dynamics

Majed Chergui

I discuss the recent developments concerning emerging ultrafast sources of short wavelength radiation, as well as the new methods they generate. I then dwell on a few examples of recent results and the way the new sources will bring major advancements in o ...

Royal Society of Chemistry2014

A cascade through spin states in the ultrafast haem relaxation of met-myoglobin

Majed Chergui, Olivier Christian Bräm, Frank van Mourik, Cristina Consani, Gerald Auböck

We report on a study of the early relaxation processes of met-Myoglobin in aqueous solution, using a combination of ultrafast broadband fluorescence detection and transient absorption with a broad UV-visible continuum probe at different pump energies. Reco ...

American Institute of Physics2014

A microfluidic flow-cell for the study of the ultrafast dynamics of biological systems

Majed Chergui, Adrien Alexis Paul Chauvet

The study of biochemical dynamics by ultrafast spectroscopic methods is often restricted by the limited amount of liquid sample available, while the high repetition rate of light sources can induce photodamage. In order to overcome these limitations, we de ...

American Institute of Physics2014

X-ray Spectroscopic Study of Solvent Effects on the Ferrous and Ferric Hexacyanide Anions

Majed Chergui, Ursula Röthlisberger, Ivano Tavernelli, Marco Eli Reinhard, Mercedes Hannelore Rittmann-Frank, Thomas James Penfold

We present an Fe K alpha resonant inelastic X-ray scattering (RIXS) and X-ray emission (XES) study of ferrous and ferric hexacyanide dissolved in water and ethylene glycol. We observe that transitions below the absorption edge show that the solvent has a d ...

2014

Characterizing the Structure and Defect Concentration of ZnO Nanoparticles in a Colloidal Solution

Majed Chergui, Camelia Borca, Marco Eli Reinhard, Mercedes Hannelore Rittmann-Frank, Thomas James Penfold, Jochen Rittmann, Thomas Charles Henry Rossi

The structure and defect concentration of colloidal solutions of ZnO nanoparticles, synthesized by a sol gel procedure (SG-NP), as well as commercially available ZnO nanoparticles (SA-NP) are investigated by UV-vis absorption spectroscopy, transmission ele ...

Amer Chemical Soc2014

Ultrafast Relaxation Dynamics of Osmium-Polypyridine Complexes in Solution

Mohammad Khaja Nazeeruddin, Majed Chergui, Olivier Christian Bräm, Andrea Cannizzo

We present steady-state absorption and emission spectroscopy and femtosecond broadband photoluminescence up-conversion spectroscopy studies of the electronic relaxation of Os(dmbp)(3) (Os1) and Os(bpy)(2)(dpp) (Os2) in ethanol, where dmbp is 4,4'-dimethyl- ...

American Chemical Society2013

Coupling of a high-energy excitation to superconducting quasiparticles in a cuprate from coherent charge fluctuation spectroscopy

Majed Chergui, Ahmad Odeh, Fabrizio Carbone, Andreas Helmut Christian Mann, Mariateresa Scarongella

Dynamical information on spin degrees of freedom of proteins or solids can be obtained by NMR and electron spin resonance. A technique with similar versatility for charge degrees of freedom and their ultrafast correlations could move the understanding of s ...

National Academy of Sciences2013

Ultrafast Solvent-Assisted Electronic Level Crossing in 1-Naphthol

Majed Chergui, Olivier Christian Bräm, Mirabelle Prémont-Schwarz

Wiley-Blackwell2013

Page 7 sur 13