Researchers capture first images of atoms
Ultra-fast camera captures nitrogen atom, paves path toward atomic-scale chemistry.
Columbus, Ohio – Using a new ultrafast camera, researchers have recorded the first real-time image of two atoms vibrating in a molecule. Key to the experiment was the researchers’ use of the energy of a molecule’s own electron as a kind of “flash bulb” to illuminate the molecular motion.
The team used ultrafast laser pulses to knock one electron out of its natural orbit in a molecule. The electron then fell back toward the molecule scattered off of it, analogous to the way a flash of light scatters around an object, or a water ripple scatters in a pond.
Principal investigator Louis DiMauro of Ohio State University said that the feat marks a first step toward not only observing chemical reactions, but also controlling them on an atomic scale.
“Through these experiments, we realized that we can control the quantum trajectory of the electron when it comes back to the molecule, by adjusting the laser that launches it,” said DiMauro, who is a professor of physics at Ohio State. “The next step will be to see if we can steer the electron in just the right way to actually control a chemical reaction.”
A technique called laser induced electron diffraction (LIED) is commonly used in surface science to study solid materials. Here, the researchers used it to study the movement of atoms in a single nitrogen, or N2, and oxygen, or O2 molecule. In each case, the researchers hit the molecule with laser light pulses of 50 femtoseconds, or quadrillionths of a second. They were able to knock a single electron out of the outer shell of the molecule and detect the scattered signal of the electron as it re-collided with the molecule.
Beyond its potential for controlling chemical reactions, the technique offers a new tool to study the structure and dynamics of matter, he said. “Ultimately, we want to really understand how chemical reactions take place. So, long-term, there would be applications in materials science and even chemical manufacturing.”