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.
DiMauro and Ohio State postdoctoral researcher Cosmin Blaga likened the scattered electron signal to the diffraction pattern that light forms when it passes through slits. Given only the diffraction pattern, scientists can reconstruct the size and shape of the slits. In this case, given the diffraction pattern of the electron, the physicists reconstructed the size and shape of the molecule that is, the locations of the constituent atoms' nuclei.
The key, explained Blaga, is that during the brief span of time between when the electron is knocked out of the molecule and when it re-collides, the atoms in the molecules have moved. The LIED method can capture this movement, "similar to making a movie of the quantum world," he added.
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."
"You could use this to study individual atoms," DiMauro added, "but the greater impact to science will come when we can study reactions between more complex molecules. Looking at two atoms that's a long way from studying a more interesting molecule like a protein."
|Contact: Louis DiMauro|
Ohio State University