Right in time for spooky season, scientists have discovered the existence of something called the “demon” particle. While the name of the material may strike terror in some, its discovery is actually far less sinister. Hidden from researchers for over seven decades, the “composite” of electrons was recently discovered according to a new study published in Nature.

“Demons have been theoretically conjectured for a long time, but experimentalists never studied them,” paper senior author Peter Abbamonte said in the study. “In fact, we weren’t even looking for it. But it turned out we were doing exactly the right thing, and we found it.”

If you could quickly predict the reactivity of a material in different scenarios using only its atomic-level geometry, you’d hold the golden ticket to finding application-specific catalytic materials. Some methods exist for making these predictions, but they require detailed knowledge about the arrangement of the atoms and are computationally expensive to perform and thus slow to run. Now Evan Miu and his colleagues at the University of Pittsburgh have developed a method that requires only information about the connectivity of the atoms, is computationally cheap, and is quick to run [1]. Their method accurately predicts how metal oxides interact with hydrogen in a reaction important to energy storage and catalysis.

Miu and the team hypothesized that they could predict a material’s reactivity using a single number that describes the so-called global connectivity of the system’s atoms. A material with a high global connectivity contains atoms that are, on average, bonded to more of their neighbors than does a system with a low value of this parameter. The researchers have used a similar concept to study reactivity for metal catalysts, but not for more complex structures, such as metal oxides.

To test their idea, the researchers examined—in different metal oxides—so-called hydrogen intercalation, a type of redox reaction that alters the host material’s properties. They found that they could use each oxide’s global connectivity to determine the strength of its hydrogen reactivity. The model-determined values for the various hydrogen-binding energies agree with experimental data and took mere seconds to obtain. The tool could thus allow scientists to rapidly develop and optimize novel materials to use in energy-storage applications.

There are several perfectly good reasons why water isn’t a popular medium for calligraphers to write in. Constantly shifting and swirling, it doesn’t take long for ink to diffuse and flow out of formation.

An ingenious ‘pen’ developed by the researchers from Johannes Gutenberg University Mainz (JGU) and the Technical University of Darmstadt in Germany, and Huazhong University of Science and Technology in China, could give artists a whole new medium to work with.

The new device is a tiny, 50 micron-wide bead made of a special material that exchanges ions in the liquid, creating zones of relatively low pH. Traces of particles suspended in the water are then drawn to the acidic solution. Drawing out that zone can create persistent, ‘written’ lines.