Science Highlights | U.S. DOE Office of Science (SC)

A long-predicted ultrafast isomerization in the UV photochemistry of bromoform is visualized for the first time by femtosecond time-resolved electron diffraction. At 267 nm excitation, the reaction pathway surpasses direct dissociation by a 60:40 margin.

Bromoform Molecules Like to Rearrange Their Atoms

Ultrafast electron diffraction imaging reveals atomic rearrangements long suspected to be crucial in the photochemistry of bromoform.

Peroxide (OO) forms on CuO by annealing in O<sub>2</sub>, leading to a larger oxygen surface population. Greater oxygen coverage prevents organic species from reacting on the oxygen-rich CuO surface (bottom right) and promotes hydrogen gas decomposition (top right).

Tuning the Catalytic Behavior of Metal Oxides

Excess oxygen on the surface of the metal oxide catalyst copper oxide promotes hydrogen oxidation but suppresses carbon monoxide oxidation.

The Belle II experiment at the SuperKEKB accelerator measures particle interactions with extreme precision. Collisions of electron and positron beams create the high-energy environment needed to produce subatomic particles that do not otherwise exist in nature.

Belle II Detector Produces World’s Most Precise Measurements of Subatomic Particle Lifetimes

Particle lifetime measurements with early data from the Belle II experiment at the SuperKEKB accelerator demonstrate the experiment’s high precision.

Researchers retrieved the time-varying molecular structure of photoexcited o-nitrophenol from ultrafast electron diffraction data using a genetic algorithm

Speedy Nuclei Do the Twist

Ultrafast electron imaging captures never-before-seen nuclear motions in hydrocarbon molecules excited by light.

Copper X-ray absorption spectroscopy measurements of catalysts in action demonstrate light-driven oxidation of copper nanoparticles under photocatalytic operating conditions.

X-ray Measurements Reveal an Unexpected Role for Copper in Photocatalysts

Copper catalysts play an unexpected oxidizing role during unassisted photocatalysis when coupled with plasmonic light absorbers.

Depiction of the dynamic atomic and nanoscale evolution of a relaxor ferroelectric following photoexcitation. Light drives ultrafast reconfigurations of the domains and rotation of the ferroelectric polarization in a few trillionths of a second.

Light Makes Special Materials Move at Ultrafast Speeds

Ultrafast electron scattering measurements reveal dynamic reconfiguration of polarization in relaxor ferroelectrics by light.

A computer that uses electronic synapses made of terminals with a top electrode (TE), dielectric layer (DL), and bottom electrode (BE) can emulate the human brain. A neural network using these synapses shows improved image recognition in an MNIST test.

Emergent Device Boosts Neuromorphic Computing

Researchers open a new avenue for future brain-inspired computer hardware.

Robotic stacking of 2D material layers on a heated substrate while applying pressure pushes out residues such as polymers from between the layers, resulting in atomically clean interfaces between layers (Bottom inset: TEM cross section of the interface).

For Layered 2D Materials, Robotics Produces Cleaner Interfaces Between Stacked Sheets

Robotic stacking of 2D layers provides the atomically clean interfaces critical for high performance assembled materials.

Visualization of a 3D assembly of DNA-guided nanoparticles and frameworks (top). Multi-element template (teal) framework of tetrahedra (bottom). Zoomed-in portion shows iron (Fe), silica, platinum (Pt), and gold (Au).

“Seeing” More Sharply into Self-Assembled Nanomaterials

Researchers leveraged advanced X-ray imaging for a nondestructive way to peer inside complex 3D nanomaterials with record resolution.

Microscope image of one of the small fragments of asteroid 162173 Ryugu studied by scientists at the Advanced Photon Source. This fragment is roughly 400 microns in diameter, or about the width of six human hairs.

Illuminating the Journey of a 4-Billion-Year-Old Asteroid

By examining tiny fragments from one of our nearest cosmic neighbors, scientists uncovered more about the history of our solar system.

A gas-phase X-Ray scattering experiment captures cyclopentadiene rapidly transforming into the strained bicyclo[2.1.0]pentene. This structure change is triggered by a pump pulse (blue) and detected through X-ray scattering (yellow).

Carbon Rings Under Stress

Ultrafast X-ray experiments provide direct evidence that interaction of light with a hydrocarbon molecule produces strained molecular rings.

A metallic line atop a medium biased at the edge of chaos can provide effective negative resistance for time-varying signals, outputting a larger signal compared to its input. The energy for amplification comes from the static bias applied to the medium.

The “Edge of Chaos” Amplifies Signals Without Transistors

Emulating the edge of chaos of axons enables a metal wire to overcome its resistance without cooling, thereby amplifying signals flowing inside of it.