First-ever images of atoms moving in a molecule captured

By Chae Hee-mook

Using a new ultrafast camera, researchers have recorded the first real-time image of two atoms vibrating in a molecule, Science Codex reported Wednesday.

Key to the experiment, which appears in this week's issue of the journal Nature, is 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 standard technique for imaging a still object involves shooting the object with an electron beam ­ bombarding it with millions of electrons per second. The researchers' new single-electron quantum approach allowed them to image rapid molecular motion, based on theoretical developments by the paper's coauthors at Kansas State University.

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.

Antimatter atom measured

Meanwhile, researchers at CERN, in an international effort led by a Canadian team, have used microwaves to manipulate antihydrogen atoms, MarketWatch reported on that day. In doing so, they've provided the world with its first glimpse of an "anti-atomic fingerprint." Their work is published today in the prestigious journal Nature, their third different Nature publication in a little more than a year.

"Our team was able to peek behind the curtain where no one has looked before by witnessing the first-ever microwave interactions with an anti-atom," says co-author Rob Thompson, a physicist at the University of Calgary and a member of the ALPHA collaboration. "This is an exciting breakthrough. Catching this glimpse of antihydrogen atoms will help our efforts to unravel some of the mysteries of our universe."

Antimatter is a staple of science fiction, but it also stands out as one of the biggest mysteries of science fact. Fundamental theories predict perfect symmetry between matter and antimatter, but the glaring absence of antimatter in our universe suggests there might be a difference. Enter microwave spectroscopy, one of the most sensitive techniques for probing the structure of atoms.

The present measurement involved confining anti-atoms in a magnetic trap and irradiating them with microwaves. Precise tuning of the microwave frequency and magnetic field enabled researchers to hit an internal resonance, kicking atoms out of the trap and revealing information about their properties.