Thinking of X-rays might trigger memories of broken bones or dental check-ups. But this extremely energetic light can show us more than just our bones: it is also used to study the molecular world, even biochemical reactions in real-time. One issue, though, is that researchers have never been able to study a single atom with X-rays. Until now.
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 ones), but they also managed to study the chemical behavior these atoms were showing.
“We can now detect exactly the type of a particular atom, one atom-at-a-time, and can simultaneously measure its chemical state,” senior author Professor Saw Wai Hla, from the University of Ohio and the Argonne National Laboratory, said in a statement.
The work was able to track an iron atom and an atom of terbium, an element that is part of the so-called rare-earth metals. Both of them were inserted in their respective molecular hosts. A conventional X-ray detector was supplemented with an extra special one. This latter one had a specialized sharp metal tip that had to be placed very close to the sample to collect the X-ray-excited electrons. From the measurements collected by the tip, the team might tell if it was iron or terbium, and that’s not all.
“We have detected the chemical states of individual atoms as well,” Hla explained. “By comparing the chemical states of an iron atom and a terbium atom inside respective molecular hosts, we find that the terbium atom, a rare-earth metal, is rather isolated and does not change its chemical state while the iron atom strongly interacts with its surrounding.”
The signal seen by the detector has been compared to fingerprints. It allows researchers to understand the composition of a sample,