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Category: chemistry

XXP instrument back online, marking a key milestone in high-energy upgrade to SLAC’s X-ray laser

XPP, the X-ray Pump Probe instrument at the Linac Coherent Light Source (LCLS), is back online and welcoming researchers after a complete rebuild. The overhaul has readied XPP for the significant increase in X-ray output expected from the ongoing high-energy upgrade to LCLS at the Department of Energy’s SLAC National Accelerator Laboratory. LCLS is a pioneering X-ray free-electron laser facility used by scientists around the world to capture ultrafast snapshots of natural processes.

“Completing the XPP rebuild on-time and on-budget is a key milestone for the high-energy upgrade effort, and we’re thrilled that the instrument is back to supporting researchers from around the world,” said John Hogan, project director for the LCLS high-energy upgrade. “This was a huge team effort, involving partners across SLAC’s engineering, science and project teams.”

Since its 2010 debut, XPP has enabled groundbreaking research across materials science—from quantum information storage to material dynamics across timescales—as well as studies in chemistry, physics and bioscience. Researchers have leveraged XPP to pioneer X-ray optics technologies, including cavity-based X-ray oscillators that are shaping future X-ray free-electron laser facilities.

Twisting water reveals hidden order across four molecular layers at air-water interface

Researchers from the Department of Physical Chemistry at the Fritz Haber Institute and Freie Universität Berlin have revealed the arrangement of water molecules at the interface between liquid water and air. Their findings help to better understand interfacial chemistry, which is largely determined by the specific arrangement of the water molecules. Published in Science Advances, the study shows that one parameter in particular—one that has been neglected until now—is of fundamental importance: the water twist.

Water is arguably the most important molecule on Earth. Interfaces of water play a critical role in numerous processes within physiology, at the ocean surface, and in the atmosphere. In these processes, it is primarily the incredibly thin region of water directly at the boundary that governs their behavior.

Crucially, the sheer presence of the interface perturbs the molecular structure of water, generating preferential orientations and an altered hydrogen-bond network, which give rise to profoundly different properties of water in that region. While these unique structures are at the heart of many interfacial phenomena, characterizing them is monumentally difficult.

Perovskite solar cells skip yellow phase, degrade more slowly with key additives

Halide perovskites are gaining ground on silicon as a critical material for solar cell technologies: A new study published in the journal Science reports a method to make perovskite-based photovoltaics more durable, allowing the films to attain the desirable black phase of crystal configuration quicker and at lower temperatures while also making it harder to degrade into the inactive yellow phase.

Perovskites are solution-processable materials and can be readily processed as a solution or deposited as vapor. By mixing two key ingredients in the precursor solution, Rice University chemical engineer Aditya Mohite and collaborators have developed perovskite crystalline films that retain 98% of their initial efficiency even after 1,200 hours of exposure under open-circuit voltage conditions to accelerate aging at 90 degrees Celsius (194 degrees Fahrenheit).

The two additives used were a two-dimensional perovskite, which served as a template to guide crystal growth, and formamidinium chloride, a salt molecule that regulates crystallization and has the optimal size to sustain the atomic bonds in the crystal in the right configuration. The two additives create compressive strain in the lattice, driving the formation of the black perovskite phase and stabilizing it, while also steering degradation toward a harder-to-form phase, significantly improving durability.

Room-temperature multiferroic could pave way to low-energy computing

A team of researchers at Rice University has engineered a new version of a well-known multiferroic that exhibits orders of magnitude higher performance at room temperature than its parent material. The study, published in the Proceedings of the National Academy of Sciences, describes a modified version of bismuth ferrite that shows a 10-fold increase in magnetization and 100-fold increase in magnetoelectric coupling compared to standard varieties.

The synthesis process entailed mixing bismuth ferrite with barium titanate while simultaneously growing the material as a thin film on a substrate that distorts its crystal structure.

“Nobody had ever dialed both knobs—the strain and the chemistry—at once,” said Rice materials scientist Lane Martin, who led the study. “We were able to combine two different material systems into a new material with a new structure and a new combination of properties.”

Superconducting quantum circuit simulates proton tunneling phenomenon in chemical systems

Researchers at Yale, Google, and the University of California-Santa Barbara have created a device that simulates the quantum “tunneling” behavior of protons that occurs in chemistry, a process so common it occurs in everything from photosynthesis to the formation of human DNA.

The advance has the potential to aid researchers across a variety of disciplines, including the development of new solar fuels, pharmaceuticals, and materials. It is described in a new study in the journal PRX Quantum.

Quantum tunneling is a mechanism by which particles, such as electrons or protons, pass through an energy barrier they should not have sufficient energy to cross.

Gene circuits reshape DNA folding and affect how genes are expressed, study finds

When a gene is turned on in a cell, it creates a ripple effect along the DNA strand, changing the physical structure of the strand. A new study by MIT researchers, appearing in Science, shows that these ripples can stimulate or suppress neighboring genes. These effects, which result from the winding or unwinding of neighboring DNA, are determined by the order of genes along a strand of DNA. Genes upstream of the active gene are usually turned up, while those downstream are inhibited.

The new findings offer guidance that could make it easier to control the output of synthetic gene circuits. By altering the relative ordering and arrangement of genes (gene syntax), researchers could create circuits that synergize to maximize their output, or that alternate the output of two different genes.

“This is really exciting because we can coordinate gene expression in ways that just weren’t possible before,” says Katie Galloway, an assistant professor of chemical engineering at MIT. “Syntax will be really useful for dynamic circuits. Now we have the ability to select not only the biochemistry of circuits, but also the physical design to support dynamics.”

Chemists stabilize rare three‑atom metal ring, revealing new form of aromaticity

In a world first, the team, led by Professor Stephen Liddle, discovered a new type of aromatic molecule made entirely of metal atoms, the heaviest of its kind ever confirmed. The team stabilized an extremely rare three‑atom ring of bismuth, held between two large metal atoms (uranium or thorium) in a structure known as an “inverse‑sandwich” complex.

This breakthrough provides fresh insight into one of chemistry’s most familiar concepts—aromaticity—and shows it can occur not only in carbon‑based rings like benzene, but also in unusual clusters of heavy metals. The paper is published in the journal Nature Chemistry.

Computer-designed thermoelectric generator achieves more than 8-fold improvement in efficiency

A thermoelectric generator with a shape that no human designer would likely have imagined has now been created by a computer—and it performs more than eight times better than conventional designs. Rather than relying on intuition or repeated trial and error, the breakthrough was achieved through advanced computational optimization.

A joint research team led by Professor Jae Sung Son of the Department of Chemical Engineering at POSTECH (Pohang University of Science and Technology), in collaboration with Professor Hayoung Chung of the Department of Mechanical Engineering at UNIST (Ulsan National Institute of Science and Technology), has developed a general design framework that enables computers to autonomously identify the optimal structure of thermoelectric generators, which convert waste heat into electricity.

Their work is published online in Nature Communications.

New microscope reveals previously hidden differences in photosynthetic light-harvesting antennae

How do photosynthetic organisms harvest light so efficiently? To help answer this question, researchers have developed an ultrafast transient absorption microscope with sensitivity approaching the single-molecule level.

Plants and photosynthetic bacteria have a wide variety of light-harvesting antennae in which pigment molecules are precisely arranged to utilize light energy efficiently. However, these molecular arrangements are not perfectly uniform and vary from particle to particle because of conformational distortions and fluctuations. Such structural variations are considered to perturb excited states and energy transfer processes triggered by light absorption. Because these early excitation dynamics initiate a cascade of photosynthetic photochemical reactions, understanding the effects of such fluctuations and heterogeneities is essential for revealing how phototrophic organisms maintain efficient and stable photosynthesis.

To analyze these fluctuations and heterogeneities, single-molecule fluorescence spectroscopy has been widely utilized. However, the fluorescence-based approach faces fundamental challenges in observing ultrafast and multistep processes, as well as non-fluorescent dark states and radical species.

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