First-ever X-ray of a Single Atom by Scientists

It has never been possible to use an X-ray to scan a single iron atom hidden within a complicated molecule, according to the work of Ohio University physicist Saw Wai Hla and his colleagues.

Because we live in the future, incredibly strong microscopes are able to capture photos of individual atoms—in fact, they do it almost constantly. However, pictures by themselves are unable to identify the element a scientist is studying without the aid of X-rays and spectroscopy, which determines an object’s “chemical fingerprint” by measuring the wavelengths of light it absorbs or emits.
Hla and his associates have identified individual atoms and tested several important features of them in recent research.

The researchers employed a method known as scanning tunneling microscopy, which makes use of a conductive tip to scan a sample’s surface, in conjunction with strong, concentrated X-rays from a particle accelerator known as a synchrotron to do this. “To use X-ray spectroscopy at the ultimate limit of atomic scale” was their objective, Hla explains to Inverse. Despite being developed nearly 130 years ago in 1895, X-rays have never been able to identify a single atom.

Swift Electrons and Radiant Lumens

Electrons are accelerated to almost the speed of light in a synchrotron, such as the one at Argonne National Laboratory in Illinois, and then sent whizzing around a curving track. Imagine a small version of Tron as the racing electrons flash dazzling light as they negotiate each track curve. The synchrotron is equipped with equipment that divides light into distinct wavelengths. For example, the X-ray radiation is sent down one beamline and the infrared light down another.
The X-rays generated in this manner are more concentrated and brighter than those obtained from a standard X-ray equipment. Scientists can discover minute details about a material’s composition and structure by observing how light interacts with its molecules.

However, how small is small? For example, you better hope your sample has a few thousand iron atoms or more if you want to determine if iron is present in a certain substance, as the synchrotron X-ray will likely miss it.

However, materials scientists have excellent reason to be interested in identifying individual atoms in considerably smaller quantities.

“There will be a huge impact in many research areas if one can detect the elemental and chemical state of an atom,” claims Hla.

The Domain of Quantum Optics

Quantum tunneling is useful in this situation. The atoms in a sample receive an energy boost from the synchrotron X-rays. Some of the electrons orbiting closest to the atom’s center become agitated by that fresh energy arising and managing to break loose.

The sample was held by Hla and his colleagues at a distance of only half a nanometer from the sharp metal tip of a scanning tunneling microscope instrument. This was close enough to create a quantum tunnel that allowed the freshly released electrons from the sample to enter the instrument.

The information carried by the electrons that reach the detector tip about the atom they originated from, including the X-ray light wavelengths that the atom absorbed, is revealed. Knowing which wavelengths the sample absorbed can identify the precise element an electron originated from because every chemical element has a unique set of light wavelengths that it absorbs, reflects, and emits.

Here, too, Hla and his associates had just scanned the lone iron atom within a massive, intricate molecule in the form of a ring. The scan also showed that the iron atom in question was missing two electrons. It’s crucial to understand it since it affects how an atom can interact with other atoms to create new chemical bonds.

Next Steps

Hla and his associates carried out the experiment once more using a large, complex molecule that contained a single atom of the rare-earth element terbium. And once more, the terbium atom and its chemical state were detected by the detector.

For engineers and materials scientists in the future, being able to combine fine-grained images with X-ray scans of a single atom of such a valuable element might be quite beneficial.

According to Hla, “it might also be useful in medical research.” “To mention a few, it will have an effect on quantum information science as well.” Hla adds that his team’s next goal is to measure an atom’s magnetic characteristics, which will be helpful for solid-state electronics.

Scientists X-ray a Single Atom for the First Time (msn.com)

First-ever X-ray of a Single Atom by Scientists

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