Published on September 16th, 2012 | by James Ayre
Atomic Bonds Discernible In New Single-Molecule Images
Researchers from IBM in Zurich have published new images of single molecules that are so high resolution that it’s possible to see the specific types of atomic bonds between their atoms.
This is the same research team that took the first single-molecule image ever captured, and also, more recently took images of the synthetic molecule Olympicene.
This new ability is opening up the possibility of studying the ‘imperfections’ in the potentially revolutionary material graphene, or in “plotting where electrons go during chemical reactions.”
The research and images were just published in the journal Science.
The research team, which included Spanish and French contributors, got the images by using a “variant of a technique called atomic force microscopy, or AFM.”
“AFM uses a tiny metal tip passed over a surface, whose even tinier deflections are measured as the tip is scanned to and fro over a sample.”
“This carbon monoxide molecule effectively acts as a record needle, probing with unprecedented accuracy the very surfaces of atoms.”
The extreme precision of these measurements couldn’t really be overstated — they are in a class of their own.
Carried out “at a scale so small that room temperature induces wigglings of the AFM’s constituent molecules that would blur the images, so the apparatus is kept at a cool -268C.”
The research was done primarily to observe the “tiny distortions to the regular hexagonal pattern of carbon bonds. The new study examined fullerenes – such as the famous football-shaped ‘buckyball’ – and polyaromatic hydrocarbons, which have linked rings of carbon atoms at their cores.”
“The images show just how long the atomic bonds are, and the bright and dark spots correspond to higher and lower densities of electrons,” the news release states.
“Together, this information reveals just what kind of bonds they are — how many electrons pairs of atoms share — and what is going on chemically within the molecules.”
“In the case of pentacene, we saw the bonds but we couldn’t really differentiate them or see different properties of different bonds,” Dr Gross said.
“Now we can really prove that… we can see different physical properties of different bonds, and that’s really exciting.”
Going on the news release added:
“The team will use the method to examine graphene, one-atom-thick sheets of pure carbon that hold much promise in electronics.
“But defects in graphene — where the perfect sheets of carbon are buckled or include other atoms — are currently poorly understood.”
The researchers intend to investigate the possible use of different molecules as their “record needle,” potentially providing more and varied insight into the world of the molecule.