Stochastic atomic acceleration during the X-ray-induced fluidization of a silica glass

Abstract

The X-ray-induced, nonthermal fluidization of the prototypical SiO 2 glass is investigated by X-ray photon correlation spectroscopy in the small-angle scattering range. This process is initiated by the absorption of X-rays and leads to overall atomic displacements which reach at least few nanometers at temperatures well below the glass transition. At absorbed doses of ∼5 GGy typical of many modern X-ray-based experiments, the atomic displacements display a hyperdiffusive behavior and are distributed according to a heavy-tailed, Lévy stable distribution. This is attributed to the stochastic generation of X-ray-induced point defects which give rise to a dynamically fluctuating potential landscape, thus providing a microscopic picture of the fluidization process.

A new experimental setup for combined fast differential scanning calorimetry and X-ray photon correlation spectroscopy

“…The effect we are probing is thus induced by the X-ray beam itself and is referred to as 'beam-induced dynamics' (Ruta et al, 2017). It is observed in different oxide glasses such as borates and silicates (Ruta et al, 2017;Pintori et al, 2019;Dallari et al, 2023;Martinelli et al, 2023), and it is characterized by a relaxation time inversely proportional to the incident X-ray flux. This effect is due to electronic excitations that couple with the lattice and induce atomic displacements.…”

High-pressure X-ray photon correlation spectroscopy at fourth-generation synchrotron sources

“…To date, experimental studies of the relaxation dynamics in glass-formers have focused on the temperature dependence of the atomic motion (Amini et al, 2021;Wang et al, 2015), its response to external mechanical and thermal stresses Ku ¨chemann et al, 2018;Luo et al, 2020;Das et al, 2020), or to its interaction with intense X-ray beams in the case of oxide and chalcogenide glasses (Martinelli et al, 2020;Alfinelli et al, 2023;Dallari et al, 2023;Li et al, 2022;Pintori et al, 2019).…”

In situ aggregation and early states of gelation of gold nanoparticle dispersions

“…31 XPCS is frequently used to study soft matter systems, e.g. , obtaining structural and dynamical information of diffusion and hydrodynamic interactions on microsecond timescales, 32–37 glasses and glass transitions, 38–45 and colloidal gelation. 43,46–53 Recently, we have used XPCS to study the gelation of colloidal gold particles grafted with polyethylene (PEG) based ligands and dispersed in a water–glycerol mixture.…”

“…4,10,30 To track these processes, X-ray photon correlation spectroscopy (XPCS) at modern X-ray light sources allows both the necessary spatial resolution covering nm length scales as well as time resolution of sub-ms to probe the dynamics of the particles in real time. 31 XPCS is frequently used to study soft matter systems, e.g., obtaining structural and dynamical information of diffusion and hydrodynamic interactions on microsecond timescales, [32][33][34][35][36][37] glasses and glass transitions, [38][39][40][41][42][43][44][45] and colloidal gelation. 43,[46][47][48][49][50][51][52][53] Recently, we have used XPCS to study the gelation of colloidal gold particles grafted with polyethylene (PEG) based ligands and dispersed in a water-glycerol mixture.…”