Achieving the world’s first X-ray of a single atom

Thinking about X-rays may bring up memories of broken bones or dental exams. But this highly energetic light can show us more than just our bones: it is also used to study the molecular world, and even biochemical reactions in real time. However, one problem is that researchers have never been able to study a single atom with X-rays. So far.

Scientists have been able to characterize a single atom using X-rays. Not only were they able to distinguish the type of atoms they were seeing (there were two different types), but they were also able to study the chemical behavior these atoms were exhibiting.

“Atoms can be routinely imaged with scanning probe microscopes, but without X-rays, one cannot tell what they are made of,” said Professor Sao Wai Hla, senior author, of Ohio University and Argonne National Laboratory, in a paper. statement.

“Once we are able to do this, we can track the material down to the limit of just one atom. This will have a huge impact on environmental and medical sciences and maybe even find a treatment that could have a huge impact on the human race. This discovery will change the world.”

The work was able to trace an iron atom and an atom of terbium, an element that is part of the so-called rare earth metals. Both have been inserted into their molecular hosts. The conventional X-ray detector has been supplemented with an additional special one. The latter had a specialized sharp metal tip that had to be placed very close to the sample to collect the X-ray-excited electrons. From measurements collected by the tip, the team can tell if it’s iron or terbium, and that’s not all.

“We also discovered the chemical states of individual atoms,” Hla explained. “By comparing the chemical states of an iron atom and a terbium atom within special molecular hosts, we find that a terbium atom, a rare earth metal, is more or less isolated and does not change its chemical state while the iron atom interacts strongly with the surroundings.”

The signal seen by the detector was compared to a fingerprint. It allows researchers to understand the composition of the sample, as well as study its physical and chemical properties. This can be critical to improving the performance and application of a variety of common and not-so-common materials.

“The technique used, and the concept demonstrated in this study, has opened up new horizons in X-ray science and nanoscale studies,” said Tululop Michael Ajay, the paper’s first author who did the work as part of his doctoral thesis. What’s more, using X-rays to detect and characterize individual atoms could revolutionize research and generate new technologies in areas such as quantitative information and trace element detection in environmental and medical research, to name a few. This achievement also opens the way for advanced devices in materials science.”

The study has been published in the journal nature.