Researchers from ULCA have captured atomic nucleation in four dimensions for the first time. The study, published in the journal Nature, might require scientists to reconsider the atomic models in different materials.
In case you didn’t know, nucleation is the merging of atoms and molecules that happens as materials change their states. Using an advanced imaging technique, scientists from UCLA were able observe the movement of atoms in four dimensions or movement across space and time.
“This is truly a groundbreaking experiment — we not only locate and identify individual atoms with high precision, but also monitor their motion in 4D for the first time,” said Jianwei “John” Miao, professor of physics and astronomy at UCLA.
During the course of their research, the scientists used a powerful electron microscope at Berkeley Lab’s Molecular Foundry to use an imaging technique called “atomic electron tomography.” As the molecular sample rotated, the microscope created 3D images of atom within a material.
Afterwards, the scientists examined iron-platinum alloy nanoparticles that were heated to 968 degrees Fahrenheit. Then the group took images of the particles after 9, 16 and 26 minutes. Interestingly, images showed that as the material heated up, its atomic structure took a more rigid pattern. However, the team tracked the same 33 nuclei within one nanoparticle.
According to the scientists, results from the experiment contradict the theory of nucleation. Previously, scientists thought that nuclei are perfectly round. However, the latest research showed that the nuclei had irregular shapes. On the other hand, although the traditional theory claims that nuclei have a sharp boundary, the researchers found that each nucleus had a core of atoms which would change to the new ordered phase. But the atoms that are closer to the center of the nuclei were more disorganized than atoms further away.