Chemistry The possibly smallest RUB script in the world
How many atoms are necessary to write the acronym of Ruhr-Universität Bochum?
The answer is 31. It takes merely this few silver atoms to legibly write RUB. Not with a pen, of course. A special technique must be deployed to manipulate the individual atoms. The Chair of Physical Chemistry I, headed by Prof Dr Karina Morgenstern, owns a device that has this capability: a low temperature scanning tunnelling microscope. It images metal surfaces with atomic resolution; in addition, it can also be used for moving individual atoms around.
Using this technique, PhD student Karsten Lucht wrote the three letters R, U and B with individual silver atoms. The three letters have a width of merely 20 nanometres in total. This is less than one thousandth of the diameter of a human hair. But why bother? “Moving individual atoms is fascinating. As our microscope has that capability, I wanted to have a go at it,” he explains. The physical chemist’s field of research is analysing individual molecules and their interaction with solvent molecules, such as water.
In the first step, Lucht applies organic molecules on a metal surface. Subsequently, he cools the sample to below ten Kelvin, i.e. lower than minus 260 degree centigrade. “At that temperature, molecular motion stops,” he explains. “Consequently, we are able to image and analyse individual molecules.”
He then adds other molecules, such as water, and monitors the way they interact with organic molecules. “An interesting and complex field,” says Karsten Lucht. His research is embedded in the Resolv Cluster of Excellence, where researchers investigate the ways in which solvents influence chemical reactions.