Publications associées à Diffractive imaging for periodic samples: retrieving one-dimensional concentration profiles across microfluidic channels

NMR Crystallography in the Big Data Era: New Methods and Applications Powered by Machine Learning

Structure determination of materials is key to understanding their physical properties. While single-crystal X-ray diffraction is the gold standard for structures displaying long-range order, many materials of interest are polycrystalline and/or disordered ...

EPFL2023

Low-energy Electron Holography Microscope for Imaging of Single Molecules

Sven Alexander Szilagyi

Structure determination techniques are an essential tool to investigate and understand molecules, especially in biology, where functionality crucially depends on structure. The dominant high-resolution methods, such as transmission electron microscopy and ...

EPFL2022

Phase Reconstruction of Low-Energy Electron Holograms of Individual Proteins

Klaus Kern, Stephan Rauschenbach, Sven Alexander Szilagyi, Hannah Julia Ochner

Low-energy electron holography (LEEH) is one of the few techniques capable of imaging large and complex three-dimensional molecules, such as proteins, on the single molecule level at subnanometer resolution. During the imaging process, the structural infor ...

AMER CHEMICAL SOC2022

Stochasticity helps to navigate rough landscapes: comparing gradient-descent-based algorithms in the phase retrieval problem

Francesca Mignacco, Lenka Zdeborová

In this paper we investigate how gradient-based algorithms such as gradient descent (GD), (multi-pass) stochastic GD, its persistent variant, and the Langevin algorithm navigate non-convex loss-landscapes and which of them is able to reach the best general ...

2021

Promising anti-cancer potency of 4,5,6,7-tetrahydrobenzo[d]thiazole-based Schiff-bases

Kurt Schenk, Farzaneh Fadaei Tirani

Four new Schiff-bases have been synthesized from the 1:2 M condensation of 4,5,6,7-tetrahydrobenzothiazole-2,6-diamine with 2-hydroxybenzaldehyde (SL3), 5-Bromo-2-hydroxybenzaldehyde (SL2), 2-hydroxy-3-methoxybenzaldehyde (SL3) and 2-hydroxy-1-naphthaldehy ...

ELSEVIER2020

Synthesis, Characterisation and Crystal structure of a New Cu(II)-carboxamide Complex and CuO nanoparticles as New Catalysts in the CuAAC reaction and Investigation of their Antibacterial activity

Kurt Schenk, Farzaneh Fadaei Tirani

The bidentate carboxamide ligand N-(thiazole-2-yl) picolinamide (LH) was synthesized in the environmentally friendly ionic liquid TBAB, and the five-coordinated Cu-II-complex, [Cu(L)(2)(H2O)]center dot CHCl3 (1) was synthesized from LH and copper(II)acetat ...

2020

Neutron Diffraction and Diffraction Contrast Imaging for Mapping the TRIP Effect under Load Path Change

Helena Van Swygenhoven, Efthymios Polatidis, Markus Strobl

The transformation induced plasticity (TRIP) effect is investigated during a load path change using a cruciform sample. The transformation properties are followed by in-situ neutron diffraction derived from the central area of the cruciform sample. Additio ...

MDPI2020

Cu-Sn-S system: Vibrational properties and coexistence of the Cu2SnS3, Cu3SnS4 and Cu4SnS4 compounds

Andrew Wayne Fairbrother

In the present study the transformation between Cu2SnS3, Cu3SnS4 and Cu4SnS4 compounds is analyzed by means of X-ray diffraction and Raman scattering spectroscopy. A detailed analysis of the X-ray diffractograms showed the dependence of formation of the in ...

PERGAMON-ELSEVIER SCIENCE LTD2020

Refinement for single-nanoparticle structure determination from low-quality single-shot coherent diffraction data

Christophe Nicolas, Christoph Bostedt

With the emergence of X-ray free-electron lasers, it is possible to investigate the structure of nanoscale samples by employing coherent diffractive imaging in the X-ray spectral regime. In this work, we developed a refinement method for structure reconstr ...

INT UNION CRYSTALLOGRAPHY2020

Characterizing crystalline defects in single nanoparticles from angular correlations of single-shot diffracted X-rays

Giorgio Rossi, Christoph Bostedt, Alessandro Colombo

Characterizing and controlling the uniformity of nanoparticles is crucial for their application in science and technology because crystalline defects in the nanoparticles strongly affect their unique properties. Recently, ultra-short and ultra-bright X-ray ...

INT UNION CRYSTALLOGRAPHY2020

Liquid phase in situ spectroscopic investigations of heterogeneous catalysts

Thibault Xavier Florian Fovanna

In this work, we have studied various aspects of catalysts and catalytic processes at the solid-liquid interface, e.g. the reduction of supported PdO, the formation of Pd hydrides, their quantification, the their reactivity in a transient in time-resolved ...

EPFL2020

Monitoring Spontaneous Charge-Density Fluctuations by Single-Molecule Diffraction of Quantum Light

Jérémy Raymond Jean Maurice Rouxel

Homodyne X-ray diffraction signals produced by classical light and classical detectors are given by the modulus square of the charge density in momentum space vertical bar sigma(q)vertical bar(2), missing its phase, which is required in order to invert the ...

2019

Advanced Computational Methods for NMR Crystallography

Albert Hofstetter

Knowledge of the atomic-level structure is key to understanding and predicting properties of materials. X-ray diffraction (XRD) is the methods of choice for structures containing well-defined long-range order. However, many materials contain various degree ...

EPFL2019

In Situ Deformation Studies of HCP Metal Alloys with Neutron Diffraction, X-Ray Diffraction, and High Resolution Digital Image Correlation

Karl Alan Sofinowski

Mg and Ti alloys are attractive materials for structural applications in the transportation and biomedical industries due to their high strength-to-weight ratios. However, due to their hexagonally close-packed (HCP) lattice structure, they exhibit poor for ...

EPFL2019

Magnetic and optical properties in degenerated transition metal and Ga co-substituted ZnO nanocrystals

Reinis Ignatans

In order to study the influence of itinerant electrons on magnetic properties of transition metal substituted ZnO nanocrystals, nanopowders containing different amounts of Ga and fixed amounts of Fe, Ni and Mn ions were synthesized. The ions of different t ...

2019

Triggered incommensurate transition in PbHfO3

Alexander Tagantsev

We report a type of structural phase transitions in dielectric materials: the triggered incommensurate (IC) transition. We demonstrate evidence for such a transition in the perovskite antiferroelectric PbHfO3 by means of single-crystal x-ray diffraction, d ...

AMER PHYSICAL SOC2019

Reentrant magnetism at the borderline between long-range antiferromagnetic order and spin-glass behavior in the B-site disordered perovskite system Ca2-x SrxFeRuO6

Philip Pattison

We report on the coexistence of magnetic order and disorder in the atomically disordered double perovskites Ca2FeRuO6 and CaSrFeRuO6. Powder x-ray and neutron diffraction were used to investigate the crystal structure and magnetic ordering of these oxides. ...

AMER PHYSICAL SOC2018

Incommensurate atomic density waves in the high-pressure IVb phase of barium

Gervais Chapuis, Alla Arakcheeva, Philip Pattison, Vladimir Dmitriev

The host–guest structures of elements at high pressure discovered a decade ago still leave many open questions due to the lack of precise models based on full exploitation of the diffraction data. This concerns in particular Ba IV, which is stable in the r ...

Int Union Crystallography2017

Pressure dependence of the structure and electronic properties of Sr3Ir2O7

Henrik Moodysson Rønnow

We study the structural evolution of Sr3Ir2O7 as a function of pressure using x-ray diffraction. At a pressure of 54 GPa at room temperature, we observe a first-order structural phase transition, associated with a change from tetragonal to monoclinic symme ...

2016

X‑ray and Neutron Scattering of Water

Livia Eleonora Bove Kado

This review article focuses on the most recent advances in X-ray and neutron scattering studies of water structure, from ambient temperature to the deeply supercooled and amorphous states, and of water diffusive and collective dynamics, in disparate thermo ...

American Chemical Society2016