Local Hydrogen Concentration and Distribution in Pd Nanoparticles: An In Situ STEM-EELS Approach.

Local detection of hydrogen concentration in metals is of central importance for many areas of hydrogen technology, such as hydrogen storage, detection, catalysis, and hydrogen embrittlement. A novel approach to measure the hydrogen concentration in a model system consisting of cubic palladium nanoparticles (Pd NPs), with a lateral resolution down to 4 nm is demonstrated. By measuring the shift of the Pd bulk plasmon peak with scanning transmission electron microscopy (STEM) combined with energy electron loss spectroscopy (EELS) during in situ hydrogen gas loading and unloading, local detection of the hydrogen concentration is achieved in TEM.

Ultrasonic Control of Polymer-Capped Plasmonic Molecules.

Plasmonic molecules (PMs) composed of polymer-capped nanoparticles represent an emerging material class with precise optical functionalities. However, achieving controlled structural changes in metallic nanoparticle aggregation at the nanoscale, similar to the modification of atomic structures, remains challenging. This study demonstrates the 2D/3D isomerization of such plasmonic molecules induced by a controlled ultrasound process.

Combination of Searches for Higgs Boson Pair Production in pp Collisions at sqrt[s]=13 TeV with the ATLAS Detector.

This Letter presents results from a combination of searches for Higgs boson pair production using 126-140  fb^{-1} of proton-proton collision data at sqrt[s]=13  TeV recorded with the ATLAS detector. At 95% confidence level (CL), the upper limit on the production rate is 2.9 times the standard model (SM) prediction, with an expected limit of 2.

Studies of the Energy Dependence of Diboson Polarization Fractions and the Radiation-Amplitude-Zero Effect in WZ Production with the ATLAS Detector.

This Letter presents the first study of the energy dependence of diboson polarization fractions in WZ→ℓνℓ^{'}ℓ^{'}(ℓ,ℓ^{'}=e,μ) production. The dataset used corresponds to an integrated luminosity of 140  fb^{-1} of proton-proton collisions at a center-of-mass energy of 13 TeV recorded by the ATLAS detector. Two fiducial regions with an enhanced presence of events featuring two longitudinally polarized bosons are defined.