Researchers have taken the first snapshots of heat bursts moving along hydrocarbon molecules.
A team led by Dana Dlott at the University of Illinois at Urbana-Champaign, anchored ends of the carbon-chain molecules to a gold surface, creating an atomic-scale carpet. A laser pulse then heated the gold base to around 800 kelvins in less than a trillionth of a second. Meanwhile, the team measured how the top of the carpet scattered light from a second laser. When heat reached the molecules' upper ends, making them jiggle, the scattered signal changed.
By repeating the experiment on hydrocarbons of different lengths, the researchers showed that the bursts traveled along single molecules at a constant speed of about 1 kilometer per second. That's much faster than heat diffuses in a macroscopic object. The findings appear in the Aug. 10 Science.