A5102748288- Material Dynamics and Properties
- Phase Equilibria and Thermodynamics
- Theoretical and Computational Physics
- Advanced X-ray Imaging Techniques
- Pickering emulsions and particle stabilization
- Spectroscopy and Quantum Chemical Studies
- X-ray Spectroscopy and Fluorescence Analysis
- Block Copolymer Self-Assembly
- Advanced Electron Microscopy Techniques and Applications
- nanoparticles nucleation surface interactions
- Laser-Plasma Interactions and Diagnostics
- Stochastic processes and statistical mechanics
- Particle Dynamics in Fluid Flows
- Quantum many-body systems
- Geophysics and Gravity Measurements
- Monoclonal and Polyclonal Antibodies Research
- Plant Water Relations and Carbon Dynamics
- Glass properties and applications
- Parallel Computing and Optimization Techniques
- Geomagnetism and Paleomagnetism Studies
- Electron and X-Ray Spectroscopy Techniques
- Particle Accelerators and Free-Electron Lasers
- Atomic and Molecular Physics
- Fluid Dynamics and Heat Transfer
- Genetic factors in colorectal cancer
Deutsches Elektronen-Synchrotron DESY
2016-2024
Hamburg Centre for Ultrafast Imaging
2021
Max Planck Institute for the Structure and Dynamics of Matter
2021
The University of Texas at Austin
2013-2016
PRG S&Tech (South Korea)
2015
University of Georgia
1980
Significance The importance of a molecular-level understanding the properties, structure, and dynamics liquid water is recognized in many scientific fields. It has been debated whether observed high- low-density amorphous ice forms are related to two distinct forms. Here, we study experimentally structure high-density as it relaxes into form. unique aspect this work combination X-ray methods, where wide-angle scattering provides evidence for at atomic level photon-correlation spectroscopy...
We have used a Monte Carlo method to study the face-centered-cubic (fcc) Blume-Capel model: $\mathcal{H}=\ensuremath{-}J\ensuremath{\Sigma}{(\mathrm{ij})}^{}{S}_{\mathrm{iz}}{S}_{\mathrm{jz}}+\ensuremath{\Delta}\ensuremath{\Sigma}{i}^{}{S}_{\mathrm{iz}}^{2}+H\ensuremath{\Sigma}{i}^{}{S}_{\mathrm{iz}}$, where $S=1$ and sum ($\mathrm{ij}$) is over $q=12$ nearest neighbors. traced out $\ensuremath{\Delta}\ensuremath{-}T$ phase boundary found tricritical point at...
Many materials with industrial applications are composed of smaller constituent particles arranged in a specific geometry. Scientists investigate how spatial dimension affects design rules, yielding results that reduce computational costs.
Dynamics and kinetics in soft matter physics, biology, nanoscience frequently occur on fast (sub)microsecond but not ultrafast timescales which are difficult to probe experimentally. The European X-ray Free-Electron Laser (European XFEL), a megahertz hard source, enables such experiments via taking series of diffraction patterns at repetition rates up 4.5 MHz. Here, we demonstrate photon correlation spectroscopy (XPCS) with submicrosecond time resolution samples the XFEL. We show that XFEL...
We demonstrate that inverse statistical mechanical optimization can be used to discover simple (e.g., short-range, isotropic, and convex-repulsive) pairwise interparticle potentials with three-dimensional diamond or cubic lattice ground states over a wide range of densities.
Grazing incidence small angle X-ray scattering (GISAXS) measurements reveal that superlattices of 1.7 nm diameter, gold (Au) nanocrystals capped with octadecanethiol become significantly more ordered when heated to moderate temperatures (50–60 °C). This enhancement in order is reversible and the superlattice returns its initially disordered structure cooled back room temperature. Disorder–order transition were estimated from GISAXS data using Hansen–Verlet criterion. Differential scanning...
We investigate the out-of-equilibrium dynamics of a colloidal gel obtained by quenching suspension soft polymer-coated gold nanoparticles close to and below its gelation point using X-ray Photon Correlation Spectroscopy (XPCS). A faster relaxation process emergent from localized motions reveals dynamically-arrested network at nanoscale as key signature process. find that slower is hyperdiffusive with compressed exponential form, consistent stress-driven processes. Specifically, we use...
Many soft-matter systems are composed of macromolecules or nanoparticles suspended in water. The characteristic times at intrinsic length scales a few nanometres fall therefore the microsecond and sub-microsecond time regimes. With development free-electron lasers (FELs) fourth-generation synchrotron light-sources, time-resolved experiments such ranges will become routinely accessible near future. In present work we report our findings on prototypical systems, charge-stabilized silica...
The aggregation and onset of gelation PEGylated gold nanoparticles dispersed in a glycerol-water mixture is studied by small-angle X-ray scattering photon correlation spectroscopy. Tracking structural dynamics with sub-ms time resolution over total experimental 8 hours corresponding to windows larger than 10
The nanometer length-scale holds precious information on several dynamical processes that develop from picoseconds to seconds. In the past decades, X-ray scattering techniques have been developed probe dynamics at such length-scales either ultrafast (sub-nanosecond) or slow ((milli-)second) time scales. With start of operation European XFEL, thanks MHz repetition rate its pulses, even intermediate μs range become accessible. Measuring fast timescales requires development new technologies as...
The gelation of PEGylated gold nanoparticles dispersed in a glycerol-water mixture is probed situ by x-ray photon correlation spectroscopy. Following the evolution structure and dynamics over 104 s, three-step process found. First, simultaneous increase Ornstein-Zernike length ξ slowdown characterized an anomalous q-dependence relaxation times τ ∝ q-6 strongly stretched intermediate scattering functions. After gel network has been established, evidenced constant ξ, show aging during second...
We use molecular simulation to construct equilibrium phase diagrams for two recently introduced model materials with isotropic, soft-repulsive pair interactions designed favor diamond and simple cubic lattice ground states, respectively, over a wide range of densities [Jain et al., Soft Matter 9, 3866 (2013)]. employ free energy based Monte Carlo techniques precisely trace the inter-crystal fluid-crystal coexistence curves. find that both display rich polymorphic behavior featuring stable...
We examine the structural and dynamic properties of confined binary hard-sphere mixtures designed to mimic realizable colloidal thin films. Using computer simulations, governed by either Newtonian or overdamped Langevin dynamics, together with other techniques including a Fokker-Planck equation-based method, we measure position-dependent average diffusivities particles along structurally isotropic inhomogeneous dimensions fluids. At moderate packing fractions, local single-particle normal...
In this paper we describe a setup for x-ray scattering experiments on complex fluids using liquid jet. The supports Small and Wide Angle X-ray Scattering (SAXS/WAXS) geometries. jet is formed by gas-dynamic virtual nozzle (GDVN) allowing diameters ranging between 1 μm 20 at length of several hundred μm. To control properties such as length, diameter, or flow rate, the instrument equipped with diagnostic tools. Three microscopes are installed to quantify dimensions stability in situ. has been...
X-ray spectroscopy is a method, ideally suited for investigating the electronic structure of matter, which has been enabled by rapid developments in light sources and instruments. The x-ray fluorescence lines life-relevant elements such as carbon, nitrogen, oxygen are located soft regime call suitable spectrometer devices. In this Letter, we present high-resolution spectrum liquid water, recorded with based on reflection zone plate (RZP) design. RZP-based meridional variation line space...
Molecular dynamics simulations and a stochastic Fokker-Planck equation based approach are used to illuminate how position-dependent solvent mobility near one or more tracer particle(s) is affected when tracer-solvent interactions rationally modified affect corresponding solvation structure. For tracers in dense hard-sphere fluid, we compare two types of interactions: (1) hard-sphere-like interaction, (2) soft repulsion extending beyond the hard core designed via statistical mechanical theory...
We study whether fine discretization (i.e., terracing) of continuous pair interactions, when used in combination with first-order mean-spherical approximation theory, can lead to a simple and general analytical strategy for predicting the equilibrium structure thermodynamics complex fluids. Specifically, we implement version this approach predict how screened electrostatic repulsions, solute-mediated depletion attractions, or ramp-shaped repulsions modify radial distribution function...
Classic hydrodynamic arguments establish that when a spherical tracer particle is suspended between parallel walls, tracer-wall coupling mediated by the solvent will cause to exhibit position-dependent diffusivity. We investigate how diffusivity profiles of confined tracers are impacted diameter size-ratio solvent: starting from classic limit infinite (i.e., continuum solvent), we consider size-ratios four or less examine predictions disrupted for systems where and similar scale. use...
Protein crystallization is dependent upon, and sensitive to, the intermolecular contacts that assist in ordering proteins into a three-dimensional lattice. Here we used protein engineering mutagenesis to affect of single chain antibody fragments (scFvs) recognize EE epitope (EYMPME) with high affinity. These hypercrystallizable scFvs are under development difficult proteins, such as membrane forming crystals, by acting chaperones. Guided analyses crystal lattice contacts, two...
Computer simulations and a stochastic Fokker-Planck equation based approach are used to compare the single-particle diffusion coefficients of equilibrium hard-sphere fluids exhibiting identical inhomogeneous static structure governed by either Brownian (i.e., overdamped Langevin) or Newtonian microscopic dynamics. The physics inhomogeneity is explored via imposition one-dimensional sinusoidal density profiles different wavelengths amplitudes. When imposed variations small in magnitude for...
Abstract We show the results of speckle contrast analysis at MID instrument European XFEL in hard X-ray regime. Speckle patterns measured from static colloidal samples are compared to previously obtained SPB/SFX instrument. A high degree coherence 0.79 is by modelling q -dependence contrast, that corresponds a number coherent modes M = 1.7. Furthermore, variation over many pulse trains exceptional low, resulting with relative standard deviation below 0.1. Our demonstrate stability properties...