Scientists ‘strummed’ a molecule’s chemical bonds like guitar strings
Like plucking a tiny guitar string, scientists have “strummed” chemical bonds. Plucking the bonds, which connect two carbon atoms separated by just 140 billionths of a millimeter, required a minuscule “pick.” A single molecule of carbon monoxide attached to the extremely thin tip of an atomic force microscope did the trick, researchers report in a paper accepted in Physical Review Letters. Atomic force microscopes image materials by measuring the forces a material exerts on the microscope’s slender tip, which is scanned across the surface (SN: 8/1/19). Physicist Jay Weymouth and colleagues used such a microscope to study molecules of perylenetetracarboxylic dianhydride, or PTCDA. They were chosen for their flat shape, which allows them to be laid on a surface for inspection. The researchers oscillated the atomic force microscope’s tip back and forth over the surface, measuring how fast the tip jiggled and how much energy was required to keep it moving. When the microscope tip was dragged over a bond, more energy was required to...