Those little hexagons you studied in high-school chemistry -- they are real things! Real, tiny, tiny things that make up the world around us, and that, with the help of an "atomic finger," we can actually see.
Using a technique called noncontact atomic force microscopy, physicists at Lawrence Berkeley National Laboratory have managed to image a single molecule immediately before and after a complex organic reaction. The molecules are about a billionth of a meter wide. The images are to appear in a forthcoming paper in Science.
The researchers hadn't set out to capture such clear pictures of the covalent bonds between the atoms. They were just trying to see what would happen when they heated their starting molecule (oligo-enediyne, which has "26 carbon atoms and 14 hydrogen atoms structured as three connected benzene rings") to 90 degrees Celsius.
Their first approach, using a scanning tunneling microscope, provided images that were too fuzzy. They decided to try the noncontact atomic force microscopy (nc-AFM) technique. Felix Fischer, one of the paper's authors, described the nc-AFM technology in a press release, saying, "A carbon monoxide molecule adsorbed onto the tip of the AFM 'needle' leaves a single oxygen atom as the probe. Moving this 'atomic finger' back and forth over the silver surface is like reading Braille, as if we were feeling the small atomic-scale bumps made by the atoms."
The resolution of the resulting images was stunning. "What you see is what you have -- the effects of the electron forces among the atoms, and even the bond order. You can distinguish single, double, and triple bonds," Fischer said. The image above shows both the starting molecule and the two most common results of the reaction.
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