Liquid carbon characterized using a free electron laserFrom common soot to precious diamonds, carbon
Liquid carbon characterized using a free electron laser
From common soot to precious diamonds, carbon is familiar in many guises, but there have been little more than glimpses of carbon in the liquid form. Researchers at the FERMI Free Electron Laser (FEL) source have now not only generated a liquid carbon sample, but have characterized its structure, tracking the ultrafast rearrangements of electron bonding and atomic coordinates that take place as their carbon samples melt. “As far as I know, that is the fastest structural transition in condensed matter,” says Emiliano Principi, principal investigator on the project.
The work fills in some of the gaps in the element’s phase diagram—a plot of its phases at different temperatures and pressures. Despite the ubiquity of carbon and the interest it garners in so many facets of science—from sensorsandsolar cellstoquantum computingandspace rocket protection systems—knowledge of its phase diagram remains patchy. Typically, as soon as solid carbon can’t take the heat, it sublimates to gas. For other materials, researchers can enroll high-pressure cells to prevent the sample expanding straight into a gas at high temperatures, but these are usually diamond, precisely the element the conditions are designed to melt.
