Publications by Wojciech Gawelda

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The authors report a femtosecond pump-probe study of photochem. of concd. aq. solns. of [Ru(bpy)3]2+, as a function of pump power (up to 2 TW/cm2) at 400 nm excitation. The transient absorption spectra in the 345-660 nm range up to 1 ns time delay enable t ...

Electronic structure changes are at the origin of the making, breaking and transformation of bonds. These changes can be visualized by measuring the geometric structure in "real-time" during the course of a chemical reaction, a biological function or a phy ...

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 ...

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 ...

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 ...

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. ...

We describe an experimental setup, which measures transient chemical changes of photoexcited solutes in disordered systems via time-resolved X-ray Absorption Spectroscopy (XAS) with picosecond temporal resolution. The setup combines a femtosecond amplified ...

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 ...

We report on the observation of the solvation shell rearrangement after abstraction of the electron from aq. I- in a laser pump/X-ray probe expt. by recording the X-ray absorption L1- and L3-edge spectra, 50 ps after laser excitation. The L1-edge spectra c ...

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 ...

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 ...

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 ...

L2,3 x-ray absorption spectra of aq. [RuII(bpy)3]2+ were recorded in its ground and excited states, 50 ps after short pulse laser excitation. Significant changes in both the XANES (x-ray Near-Edge Absorption Structure) and the EXAFS (Extended x-ray Absorpt ...

A full multiple theor. model (MXAN) is applied to fit picosecond difference x-ray absorption spectra at the Ru L3 edge upon photoexcitation of aq. [RuII(bpy)3]2+. Fitting difference spectra allows an increase in sensitivity, such that slight structural cha ...

Femtosecond fluorescence-upconversion studies of aq. [Ru(bpy)3]2+ show a short-lived vibrationally hot emission of the singlet metal-to-ligand charge-transfer state, with an ultrafast intersystem crossing (~ 10 fs) to the triplet state at const. energy (th ...

We describe an advanced setup for time-resolved x-ray absorption fine structure (XAFS) spectroscopy with picosecond temporal resoln. It combines an intense femtosecond laser source synchronized to the x-ray pulses delivered into the microXAS beamline of th ...

Wojciech Gawelda

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Photexcitation of Aqueous Ruthenium(II)-tris-(2,2'-bipyridine) with High-Intensity Femtosecond Laser Pulses

Time-resolved x-ray absorption spectroscopy of transition metal complexes

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

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

Retrieving photochemically active structures by time-resolved EXAFS spectroscopy

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

Picosecond time-resolved X-ray Absorption Spectroscopy of solvated organometallic complexes

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

Observation of the Solvent Shell Reorganization around Photoexcited Atomic Solutes by Picosecond X-ray Absorption Spectroscopy

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

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

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

Electronic and Molecular Structure of Photoexcited [RuII(bpy)3]2+ Probed by Picosecond X-ray Absorption Spectroscopy

A Full Multiple Scattering Model for the Analysis of Time-Resolved X-ray Difference Absorption Spectra

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

Broadband femtosecond fluorescence spectroscopy of [Ru(bpy)3]2+

Capturing transient electronic and molecular structures in liquids by picosecond X-ray absorption spectroscopy