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The equations of quantum mechanics require too much computer time and power when used to predict behavior in large systems. Researchers have now shown that machine learning models can mimic the basic structure from first principles, which can be very difficult to simulate directly. The result is predictions that are easy to compute and are accurate in a wide range of chemical systems.

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A charge stripper is an important component in the process the Facility for Rare Isotope Beams (FRIB) uses to create rare isotopes for scientific research. However, FRIB’s particle beam is too powerful for a conventional charge stripper. Researchers developed a new liquid-lithium charge stripper that can produce as high a charge state as a conventional solid charge stripper and last indefinitely.

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Scientists have long theorized that carbon-12 could form in stars in the “Hoyle state,” an excited form of carbon-12, then decay through the fusing of three alpha particles to form ground state carbon and energy. Researchers have now tested the role of neutron upscattering in the fusing of the alpha particles. The results indicate that upscattering plays a less important role in the formation of carbon in stars than originally thought.

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To better understand how thermoelectric devices convert thermal energy into electricity at the atomic scale, researchers used neutrons to study single crystals of tin sulfide and tin selenide. The results revealed a strong correlation between changes in the structure at certain temperatures and the frequency of atomic vibrations (phonons). This allowed the researchers to identify temperatures ideal for energy conversion and provided basic scientific knowledge for designing new thermoelectric materials.

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Colliding atomic nuclei at very high energies “melts” the boundaries of individual protons and neutrons, setting quarks and gluons to form a quark-gluon plasma (QGP). Quarks or gluons in the colliding ions sometimes scatter off one another and then split, forming parallel sprays of particles called jets. Tracking how jets lose energy, called “quenching,” allows scientists to learn about the QGP and the nuclear strong force. New results find that some quarks lose energy even before they split to form a jet.

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Garret Suen is an associate professor of Bacteriology at the University of Wisconsin – Madison, who is researching how herbivores use the microbes in their stomachs to break down cellulose into smaller molecules that can be converted into biofuels and bioproducts.

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Atoms in magnetic materials are organized into regions called magnetic domains. Within each domain, the electrons have spins that point in the same direction. Researchers have developed a magnetic material whose thickness determines whether the walls between domains have the same or alternating spin chirality, or handedness. This study demonstrates a way to change the rotational direction and occurrence of domain wall pairs, a finding that could lead to technologies based on spintronics.

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A new X-ray optics device based on optical microelectromechanical systems can harness extremely fast X-ray pulses in a device orders of magnitude smaller and lighter than conventional devices used to regulate X-ray probes. The ultrafast X-ray optics could be essential for experiments on ultra-high-speed phenomena at synchrotron particle accelerators and will help researchers study fast-evolving chemical, material, and biological processes.

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Metal parts made using laser-based additive manufacturing (AM) can have residual strain resulting from rapid heating and cooling during printing. Annealing parts after printing reduces the strain but can cause unwanted structural changes. Researchers used neutron diffraction and neutron imaging to measure strain and determine optimal annealing for metal AM parts.

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Magnetic materials are essential to applications including data storage, cell phones, motors, and sensors. Researchers have synthesized a new, extremely small, thermally stable magnetic nanoparticle based on the principle of superatoms. The superatom structure groups electronic states in electron shells. This translates into a nanoparticle with high stability and a large spin magnetic moment.

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New investigations have produced a simpler model to elegantly explain previously observed behaviors for free carrier generation in organic solar cells. The model relies on well-established scientific descriptors, Marcus theory and entropy. Previous descriptions proposed new physical phenomena, but a new, simplified model provides a unified platform for understanding processes in both solution and solid-phase systems for organic photochemical conversion.

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Plants and algae use green-tinted chlorophyll to convert high-energy sunlight into food via photosynthesis. Some cyanobacteria can survive in deep shade by using infra-red and other low-energy light to photosynthesize. They accomplish this by re-equipping their photosynthetic protein complexes with different kinds of chlorophyll that absorb lower-energy light. Researchers have now determined the molecular structures of these photosynthetic systems to understand how cyanobacteria can use low-energy light.

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Jaime Marian is a professor at UCLA in the Department of Materials Science and Engineering, studying irradiation to develop materials and improve fusion reactor designs.

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Ultrafast pulses from X-ray lasers reveal how atoms move at femtosecond timescales, but measuring the properties of the pulses is challenging. A new approach trains neural networks to analyze the pulses. Starting from low-resolution measurements, the neural networks reveal finer details with each pulse, and they can analyze pulses millions of times faster than previous methods.

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The proton-transfer and ionization process in water leads to the formation of a hydroxyl-hydronium complex, a type of hydroxyl radical. The formation process causes ultrafast structural changes and the redistribution of energy among neighboring water molecules. Thanks to recent developments in liquid phase ultrafast electron diffraction techniques, scientists can capture these processes in real time.

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Halide perovskite can make solar cells a thousand times thinner than today’s silicon solar cells. A new approach allows scientists to watch changes in the material’s structure and functional properties while the material solidifies into a thin film from solution. This gives new insight into how the material’s structure and functionality are related, aiding in future solar cell design.

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Researchers have developed an apparatus to study reactions between gas molecules and highly volatile liquids at the gas-liquid interface with new levels of detail. The apparatus directs a molecular beam onto a flat liquid surface, and when the beam scatters, a detector collects data on the speed, direction, and mass of molecules in the scattered beam. The novel approach will help scientists understand combustion engines, air pollution, and other phenomena.

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Haim Waisman develops computational models of the mechanics of materials. He focuses on fracture phenomena, such as ice breaking due to climate warming, infrastructure aging and deteriorating, energy extraction from rocks, and fractures in biomaterials such as bones.

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Scientists have found a way to “see” inside deuterons, the simplest atomic nuclei, to better understand how particles called gluons are arranged within the deuteron. These collisions can also break the deuteron apart, giving insights into what holds the proton and neutron together. The research helps scientists understand how nuclei emerge from quarks and gluons, and how the masses of nuclei are dynamically generated by gluons.

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For the first time, researchers have used ultrafast electron diffraction to observe a quantum electronic device as it operates. Researchers observed atomic-level changes in the vanadium dioxide switch over millionths of a second, leading to the discovery of a short-lived intermediate state. The results may aid in the development of high-speed, high-efficiency quantum electronics and in the use of pulsed electric fields to create new engineered materials.

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Researchers used neutrons to see how a new aluminum-cerium alloy behaves under high temperatures and pressures inside an operating internal combustion engine. Researchers fitted an AlCe cylinder head to a commercial engine, then used neutron scattering to see inside the AlCe head and the original material engine block in real time before, during, and after the operation of the engine. This method could aid research on advanced alloys for future engines and other systems.

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Roughly half of all flowering plants are polyploid, meaning that they have more than two sets of chromosomes. Scientists believe polyploidy drives adaptation by giving organisms more genetic diversity. This research compared tetraploid (four copies) and octoploid (eight copies) varieties of switchgrass, and found that octoploid switchgrasses are generalists, able to tolerate a broad range of environmental conditions and expand their range into new areas.

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Scientists suggest that water’s so-called “proton quantum effect” may be at the heart of many of the liquid’s strange properties. In this experiment with ultrafast electron diffraction, scientists observed how the hydrogen atoms in water molecules tug and push neighboring molecules when water is excited with laser light. This marks the first time that scientists have directly observed this effect in water.

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To understand how plants respond to environmental stresses, researchers examined the genes regulated by the stress hormone abscisic acid. Specifically, they examined how these genes differ between plants that are sensitive or resistant to high levels of salt in the soil. The study found that stress hormones do not always act as growth inhibiting signals.