As more precise tools emerge, science delves deeper into the structure of matter, now working with molecules and atoms. This helps in developing new drugs, materials, and even in electronics, where there’s increasing talk about the prospects of transitioning to single-atom transistors. To involve more participants in these processes, equipment needs to become simpler, and scientists are actively working on this. One of the problems in working with nanometer structures remains the measuring equipment, which is highly complex, bulky, and expensive. Even simple measurements of distances between molecules require electron microscopes and other complex equipment. Unfortunately, physical laws don’t allow the use of convenient and relatively simple optical devices for such operations, with the microscope being the most prominent example.
Researchers from the Max Planck Institute for Multidisciplinary Sciences in Germany have managed to make significant changes in measuring intramolecular distances with angstrom precision using optical methods. In fact, they were able to measure the distance of a single atom’s width without using complex instruments.
One could say that scientists made this discovery by chance. They were studying the spatial structure of proteins (protein folding) using fluorescent markers. Polypropylene-based markers, which are already used as a “ruler” in structural biology, were attached to the molecules, and then the samples were illuminated with a laser. The fluorescence of markers excited by the laser pulse was recorded as electromagnetic radiation and provided insight into the distance between the markers.
The work done allowed scientists to develop a new approach for measuring intramolecular distances in the range of 1 to 10 nanometers for typical molecules, which they called Minflux. The smallest distance that researchers could measure using this method was 0.1 nm, corresponding to the width of a single atom. This method was tested on organic molecules, but there remains the possibility that it could be used to measure distances in semiconductors, which would significantly help the development of angstrom-era electronics.