The world’s first X-ray of a single atom reveals chemistry at the smallest level: ScienceAlert

Atoms may not have bones, but we still want to know how they are put together. These tiny particles are the foundation of all natural matter (including our bones), and understanding them helps us understand the larger universe.

We currently use high-energy X-ray light to help us understand atoms and molecules and how they are arranged, as we capture diffracted beams to recreate their configurations into crystalline form.

Now, scientists have used X-rays to characterize the properties of a single atom, demonstrating that the technique can be used to understand matter at the smallest level of its building blocks.

“here,” Write an international team Led by physicist Tululop Ajayi of Ohio University and Argonne National Laboratory in the US, “we have shown that X-rays can be used to describe the elemental and chemical states of just one atom.”

X-rays are a suitable probe for characterizing materials at the atomic level because their wavelength distribution is comparable to the size of an atom.

And there are many techniques for throwing X-rays at things to see how they are put together on very small scales.

One of those Synchrotron X-raysX-rays are accelerated to high energies so they shine much more.

To try to resolve really fine scales, Ajayi and his colleagues used a technique that combines synchrotron X-rays with an atomic-scale imaging microscopy technique called scanning tunneling microscope. This uses an excellent conductive probe with a blunt tip that interacts with the test material’s electrons in what is known as “quantum tunneling”.

At very close particles (such as half a nanometer), the exact position of the electron is uncertain, causing it to smear across the space between the material and the probe; The state of the atom can then be measured in the resulting current.

Together, the two technologies are known as synchrotron X-ray scanning tunneling microscopy (SX-STM). Magnified X-rays excite the sample, and a needle-like detector collects the resulting photoelectrons. And it’s an exciting technology that opens up some amazing possibilities: Last year, the team published a paper on using SX-STM for Rotate one molecule.

This time, they went even smaller, trying to measure the properties of a single iron atom. Created separately supramolecular assemblies, including iron and terbium ions within a ring of atoms in what is referred to as a bond. One iron and six rubidium atoms were linked by terpyridine bonds. Terbium, oxygen, and bromine were linked using pyridine-2,6-dicarboxamide linkages.

These samples were then subjected to SX-STM.

The light received by the detector is different from the light emitted by the sample. Some wavelengths are absorbed by the electrons in the atomic nucleus, which means that there are some darker lines on the spectrum of the received X-rays.

The team found that these dark lines correspond to wavelengths that iron and terbium absorb, respectively. Absorption spectra can also be analyzed to determine the chemical states of these atoms.

For the iron atom, an interesting thing happened. The X-ray signal can only be detected when the tip of the probe is located exactly above the iron atom in its supramolecular structure and in very close proximity.

The researchers say this confirms the detection in the tunnel system. Because tunneling is a quantum phenomenon, this has implications for the study of quantum mechanics.

“our business,” write the researchers“connects synchrotron X-rays to the quantum tunneling process and opens up future X-ray experiments for the simultaneous characterization of the elemental and chemical properties of materials at the final single-atom limit.”

Maybe this is at least as good as the bones.

Research published in nature.