First X-ray of a single atom

June 1 () –

Physicists in the US have taken the world’s first X-ray SIGNAL (or SIGNATURE) of a single atom. They believe this groundbreaking achievement it may revolutionize the way scientists detect materials.

Since its discovery by Roentgen in 1895, X-rays have been used everywhere from medical examinations to airport security checks. An important use of X-rays in science is identify the type of materials in a sample. Over the years, the amount of materials required in a sample for X-ray detection has been greatly reduced by the development of synchrotron X-ray sources and new instruments.

To date, the smallest amount that can be X-rayed in a sample is in atograms, i.e. about 10,000 atoms or more.. This is because the X-ray signal produced by an atom is extremely weak, so conventional X-ray detectors cannot be used to detect it. According to Saw Wai Hla Hla, first author of the study and a professor at Ohio State and a researcher at Argonne National Laboratory, it is an old dream of scientists to obtain an x-ray of a single atom, which is now being performed by the research team. directed by him.

“Atoms can be routinely visualized with scanning probe microscopes, but without X-rays you can’t tell what they’re made of. Now we can detect exactly the type of a particular atom, one atom at a time, and we can measure their chemical state simultaneously,” explained it’s a statement Hla, who is also director of the Institute for Quantum and Nanoscale Phenomena at Ohio University. “Once we can do that, we will be able to trace materials down to the maximum limit of a single atom. This will have a huge impact on medical and environmental sciences and maybe even find a cure that can have a huge impact on humanity. This discovery will transform the world.”

His article, published on the cover of Nature this June 1details how the team of physicists used a specially designed synchrotron X-ray instrument on the XTIP beamline of the Advanced Photon Source and Center for Nanoscale Materials at Argonne.

For the demo, the team chose an iron atom and a terbium atom, both inserted into respective molecular hosts. To detect the X-ray signal from an atom, the research team supplemented conventional X-ray detectors with a specialized detector made of a sharp metal tip placed very close to the sample to collect X-ray excited electrons, a well-known technique. synchrotron X-ray scanning tunneling microscopy or SX-STM. X-ray spectroscopy in SX-STM is triggered by photoabsorption of core-level electrons, which constitute elemental fingerprints and is effective in directly identifying the elemental type of materials.

According to Hla, spectra are like fingerprints, each one being unique and capable of detecting exactly what it is.

“We have also detected the chemical states of individual atoms,” Hla explained. “By comparing the chemical states of an iron atom and a terbium atom within the respective molecular hosts, we found that the terbium atom, a rare earth metal, is fairly isolated and does not change its chemical state. while the iron atom strongly interacts with its surroundings.”

Many rare earth materials are used in everyday devices such as cell phones, computers, and televisions to name a few, and are extremely important in the creation and advancement of technology. Through this discovery, scientists can now identify not only the type of element, but also its chemical state, allowing them to better manipulate the atoms within different host materials. to meet the constantly changing needs in various fields.