Small-angle pump–probe studies of photoexcited nanoparticles

Abstract

X-ray scattering experiments on femtosecond laser-excited gold nanoparticle suspensions are presented. It is shown that the time-resolved pump-probe technique using the X-ray pulse structure at synchrotron sources is capable of resolving structural dynamics on the nanometer scale to high precision. The estimation of X-ray flux density allows the projection of experiments on an X-ray free-electron laser probing single nanoparticles in a one-shot exposure.

Femtosecond laser near field ablation

“…Optionally, a monochromator can be used for high-resolution experiments, which are necessary for the measurement of the powder scattering of the excited gold particles to determine the lattice spacing. For time-resolved small-angle X-ray scattering (SAXS) [91] the radiation can be used without further monochromatization due to the inherent lower resolution necessary in the disordered sample. (1), and delay units.…”

“…Here we deal with dynamical phenomena which favor an in situ probe, such as time-resolved small-angle scattering. It has been applied to the gold-particle suspension in the described pump-probe scheme [91].…”

X-ray tracking of structural changes during a subnanosecond solid-solid phase transition in cobalt nanoparticles

“…As an examples of postsynthesis modification of nanoparticle properties utilizing laser illumination of nanoparticle solutions, illumination with intense nanosecond laser pulses exciting plasmon modes at 532 nm has been shown to give rise to highly monodisperse nanoparticles in the case of Au [12]. For characterizing these processes in more detail, the structural dynamics during pulsed laser heating, melting and resolidification of Au nanoparticles have been measured with time-resolved x-ray scattering experiments [13][14][15], but the direct structural dynamics of a solid-solid phase transition has to our knowledge not been reported.…”

Global Reaction Pathways in the Photodissociation of I3− Ions in Solution at 267 and 400 nm Studied by Picosecond X‐ray Liquidography

“…As an alternative, replacement of the optical probe by structural probes, such as X-ray absorption [7][8][9][10] or X-ray diffraction, [11][12][13][14][15][16][17][18][19][20][21][22] allows us to directly obtain the detailed structural information including the structure of short-lived solute species and solvent rearrangement around the solutes. Based on this idea, time-resolved X-ray liquidography (TRXL) or so-called time-resolved X-ray solution scattering has been applied to various solution-phase molecular systems ranging from small molecules [11][12][13][14][15][16][17][18][19] and proteins [20][21][22] to nanoparticles [23][24][25] and protein-nanoparticle complexes, [26] thereby revealing the reaction pathways and intermediates of the reactions.…”