30 August 2009
Viewing the molecule
I go on holiday for one week (which included a break from newspapers and the internet) and yet things still happen. Perhaps the biggest “WOW!” moment was the image of a single molecule of Pentacene (above). A chemical that has semiconductor properties.
The BBC reported that the image was produced by researchers at IBM Research Zurich using what is known as an atomic force microscope or AFM.
The AFM used by the researchers apparently acts like a tiny tuning fork, with one of the prongs of the fork passing incredibly close to the sample and the other farther away. When the fork is set vibrating, the prong nearest the sample will experience a minuscule shift in the frequency of its vibration, simply because it is getting close to the molecule.
Comparing the frequencies of the two prongs gives a measure of just how close the nearer prong is, effectively mapping out the molecule's structure. The measurement requires extremes of precision. This means that the samples are kept under high vacuum and at extremely cold temperatures.
Lead author of the research Leo Gross told BBC News that the group is aiming to combine their ability to measure individual charges with the new technique, characterising molecules at a truly unprecedented level of detail. That will help in particular in the field of "molecular electronics", a potential future for electronics in which individual molecules serve as switches and transistors.
The science is beyond my ken but the image is, well, bloody amazing!