Publications de Wojciech Gawelda

Spin cascade and doming in ferric hemes: Femtosecond X-ray absorption and X-ray emission studies

Majed Chergui, Christopher Alexander Arrell, Wojciech Gawelda, Giulia Fulvia Mancini, Camila Bacellar Cases Da Silveira, Frederico Alves Lima, Dominik Kinschel, Oliviero Cannelli, Jérémy Raymond Jean Maurice Rouxel, Rebecca Ann Ingle

The structure-function relationship is at the heart of biology, and major protein deformations are correlated to specific functions. For ferrous heme proteins, doming is associated with the respiratory function in hemoglobin and myoglobins. Cytochrome c (C ...

National Academy of Sciences2020

Revealing hole trapping in zinc oxide nanoparticles by time-resolved X-ray spectroscopy

Majed Chergui, Thomas James Penfold, Wojciech Gawelda, Jochen Rittmann, Fabio Giacomo Santomauro

Nature Research2018

Revealing hole trapping in zinc oxide nanoparticles by time-resolved X-ray spectroscopy

Majed Chergui, Wojciech Gawelda, Thomas James Penfold, Jochen Rittmann, Fabio Giacomo Santomauro

AMER CHEMICAL SOC2018

Time-resolved x-ray absorption spectroscopy: Watching atoms dance

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

The introduction of pump-probe techniques to the field of x-ray absorption spectroscopy (XAS) has allowed the monitoring of both structural and electronic dynamics of disordered systems in the condensed phase with unprecedented accuracy, both in time and i ...

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

Structural analysis of ultrafast extended x-ray absorption fine structure with subpicometer spatial resolution : Application to spin crossover complexes

Majed Chergui, Wojciech Gawelda, Van Thai Pham, Renske Marjan van der Veen

We present a novel analysis of time-resolved extended x-ray absorption fine structure (EXAFS) spectra based on the fitting of the experimental transients obtained from optical pump/x-ray probe experiments. We apply it to the analysis of picosecond EXAFS da ...

2009

Femtosecond XANES Study of the Light-Induced Spin Crossover Dynamics in an Iron(II) Complex

Majed Chergui, Paul Beaud, Wojciech Gawelda, Van Thai Pham, Camelia Borca, Amal El Nahhas, Renske Marjan van der Veen

X-ray absorption spectroscopy is a powerful probe of mol. structure, but it has previously been too slow to track the earliest dynamics after photoexcitation. We investigated the ultrafast formation of the lowest quintet state of aq. iron(II) tris(bipyridi ...

American Association for the Advancement of Science2009

Retrieving photochemically active structures by time-resolved EXAFS spectroscopy

Majed Chergui, Wojciech Gawelda, Camelia Borca, 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

Relaxation processes of point defects in vitreous silica from femtosecond to nanoseconds

Majed Chergui, Frank van Mourik, Andrea Cannizzo, Wojciech Gawelda, Erwin Portuondo Campa, Andrea Callegari

The authors studied ultrafast relaxation of localized excited states at Ge-related O deficient centers in SiO2 using femtosecond transient-absorption spectroscopy. The relaxation dynamics exhibits a biexponential decay, which the authors ascribe to the dep ...

2008

Light-induced spin crossover probed by ultrafast optical and X-ray spectroscopies

Majed Chergui, Andrea Cannizzo, Wojciech Gawelda, Van Thai Pham, Amal El Nahhas, Renske Marjan van der Veen

The photoinduced energy and structural relaxation of aq. iron(II)-tris-bipyridine ([FeII(bpy)3]2+), upon excitation into its singlet metal-to-ligand charge transfer (1MLCT) band, and the population of its short-lived (?0.6 ns) high-spin excited state have ...

2007

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