Möbius strip-like molecule has an entirely new and bizarre shape
Representation of electrons in the “half-Möbius” shaped molecule
IBM Research and the University of Manchester
Chemists have discovered a new molecular shape, twice as strange as the winding Möbius strip.
The Möbius strip is a looped strip with a twist, such that something tiny, like an ant, would have to go around the loop twice to return to its starting point on the same side of the strip.
Igor Rončević from the University of Manchester in the United Kingdom and his colleagues discovered a molecule with an even stranger “half-Möbius” shape. Their experiment could be the first step toward a new way to design useful molecules by adjusting their 3D shapes, or topology.
“This molecule is very new and very unexpected. The appeal is not only that we have created a molecule with an unusual topology, but we have also shown that this topology is possible, and no one has really thought about it,” he says.
To make the molecule, the researchers used 13 carbon atoms and two chlorine atoms assembled in a ring shape on a thin gold surface at an extremely cold temperature. They used two specialized microscopes – an atomic force microscope and a scanning tunneling microscope – to monitor the atoms and map the properties of their electrons. In this type of molecule, the electrons are not tightly bound to their atoms; instead, electrons spread out in specific regions around atoms like tiny waves of matter.
It was the interactions between these electrons that produced the twist never before seen in the molecule. If a tiny quantum creature traveled along the atoms, it would take four turns of the ring to get back to where it started.
By nudging the molecule with a small electromagnetic pulse, the team was able to shift the molecule’s twist from left to right or untwist it. Researchers could design its topology on demand, creating another way for chemists to manipulate molecules.
To understand the new molecule and why it might even exist, the team used simulations on a conventional computer and on an IBM quantum computer. The interactions between electrons were crucial to the molecule’s new twists, and they are difficult to simulate accurately with conventional computers. But quantum computers are already built from interacting quantum objects, which allows them to perform simulations with a higher level of confidence, says Rončević.
This is an example of how quantum computers can already be useful in solving real-world chemistry problems, says IBM team member Ivano Tavernelli.
“This experiment is a remarkable achievement in several dimensions: organic chemistry, surface science, nanoscience and quantum chemistry,” says Gemma Solomon of the University of Copenhagen in Denmark.
“This is a beautiful and inspiring study that vividly introduces abstract topological concepts into the field of molecular chemistry,” says Kenichiro Itami of Japan’s RIKEN scientific institute. He says the study is a technical study feat of strength.
Dongho Kim of Yonsei University in South Korea, who pioneered earlier work on Möbius-like molecules, says that being able to switch the molecule from one shape to another is particularly interesting, because it could lead to applications in sensors. For example, molecules could switch in pre-programmed ways when exposed to magnetic fields.
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