The detailed chemical structure of a single molecule has been imaged for the first time, say researchers.

The physical shape of single carbon nanotubes has been outlined before, using similar techniques - but the new method even shows up chemical bonds.

Understanding structure on this scale could help in the design of many things on the molecular scale, particularly electronics or even drugs.

The IBM researchers report their findings in the journal Science.

It is the same group that in July reported the feat of measuring the charge on a single atom.

Fine tuning

In both cases, a team from IBM Research Zurich used what is known as an atomic force microscope or AFM.

Their version of the device 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.

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