First time recording atomic bonds

Pairs of rhenium atoms are inserted into a hollow carbon nanotube and then beamed with high-energy electrons to create an 18-second movie.

Atoms exist in a stable bond. However, capturing these bonds seems impossible because at 0.1-3.3 nanometers, the atomic bonds are half a million times smaller than the width of a human hair.

Until now, the atomic bonding process has only been simulated in classrooms and laboratories using the ball and stick model. Recently, thanks to research by British and German scientists, students and PhD students will be able to observe for 18 seconds the bonding process of two rhenium (Re) atoms.

Researchers from the University of Nottingham and the University of Ulm inserted pairs of rhenium atoms into hollow carbon nanotubes shaped like chemical test tubes. Then, use transmission electron microscopy (TEM) to create a film of the atoms. In TEM, beam a beam of high-energy electrons through the object all the way to the other end of the nanotube. The beam not only captures an active image, but also transfers energy to break chemical bonds. Using tools from Project SALVE , this two-in-one technique allows scientists to image bonded rhenium (Re2) atoms moving on a nanotube.

Describing the film of the atomic bonding process, Dr. Kecheng Cao – research assistant at Ulm University said that as Re2 moves down the nanotube, the bond length changes, the bond becomes stronger or weaker depending on the depends on the environment surrounding the atoms. In fact, at one point, when the bonds were stretched to a size larger than the atoms themselves, the bonds would break. The atom then becomes a Re2 molecule .

First time recording atomic bonds
Image of Re2 on part of a carbon nanotube. (Image: University of Nottingham).

“Since rhenium has a high atomic number, it is easier to see in TEMs than lighter elements which helps us to identify each metal atom as a black dot,” said Professor Andrei Khlobystov, a co-leader of the University of Nottingham research project. explain.

This research is a new step towards understanding the bonding between metal atoms, describing the properties of materials. The upcoming team of scientists will further investigate and analyze the structure and forces of individual molecules in real time.