To understand a molecule, you need to know the arrangement of its atoms.
Scientists have developed a new holographic technology that allows them to peek inside a molecule and figure out its exact arrangement of atoms with the highest degree of accuracy ever.
Until now, there had been no direct method to see inside of small molecules — most imaging techniques were limited to scanning their surfaces. If scientists wanted to see more, they had to rely on indirect investigation methods or theoretical predictions.
Luckily this new system, developed by physicist Tobias Lühr from the Technical University of Dortmund in Germany and his team, is much more accurate.
According to Lisa Zyga at Phys.org, the new technique involves shooting high-energy electrons at the molecule. When the electrons hit the molecule, they scatter, bouncing off in distinct patterns based on the layout of the individual atoms. Using these patterns, the researchers are able to build a hologram of the entire molecule.
Hologram of thousands of atoms inside a molecule using information from electron patterns. Photo credit: Lühr et al/American Chemical Society
This is not the first holographic technology used to image molecules. However, this new method reduces the number of marks and imperfections left by previous imaging techniques, and can distinguish between different types of atoms.
What’s more, unlike previous technologies, the new method can also handle scanning more molecules — a serious limitation that held back research until now. In fact, it can image thousands of them.
One of the biggest improvements in the technology was the use of electron waves at much higher energies than before — several thousand electron volts compared to a few hundred. Higher-energy electron waves lead to clearer pictures, because the waves can be constrained instead of spreading out, reducing scattering.
Although a single pattern made by the high-energy electron waves can provide a reliable image, the researchers improved the image quality even more by averaging and superimposing about 20 reconstructed images.
"In order to understand the physical and chemical properties of advanced materials, functional molecular adsorbates, and protein structures, a detailed knowledge of the atomic arrangement is essential," writes the team in the journal Nano Letters. "We present a general reconstruction algorithm that leads to high-quality atomic images showing thousands of atoms."
The hope is that this technology will lead to an improved understanding of the physical and chemical processes of molecular properties, as well as help in developing new materials.
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