Just like flipping a switch – in only half a picosecond

Arthur Suits, professor in the MU Department of Chemistry

COLUMBIA, Mo. – Solar cells, quantum computing and photodynamic cancer therapy. These all involve molecules switching between magnetic and nonmagnetic forms. Previously this process, called a “spin flip,” was thought to occur slowly in most cases. Now, researchers at the University of Missouri have discovered spin flips happen in one half of one trillionth of a second, or half a picosecond in the course of a chemical reaction. To understand how fast it is — watches count in seconds, sporting games are timed in 10ths of a second, and light travels just under 12 inches in one-billionth of a second. Spin flips are faster.

“A typical molecule can have two modes, either magnetic or non-magnetic,” said Arthur Suits, a professor of chemistry in the MU Department of Chemistry. “They can switch from one mode to another if they are ‘excited’ such as by absorbing light. Most molecules begin as non-magnetic, but if you excite it with light, it can switch and become a magnetic molecule, or vice versa.”