XLEAP Allows Scientists To See Attosecond Electron Motions

Scientists at the Department of Energy's SLAC National Accelerator Laboratory have invented a way to observe movements of electrons with powerful bursts of an X-ray laser. The new technique allows scientists to measure electron movements using laser bursts that are only 280 attoseconds. An attosecond is a billionth of a billionth of a second.

The technology behind the discovery is called X-ray laser-enhanced attosecond pulse generation or XLEAP. The new tech is a significant advance that scientists have been working toward for years and paves the way for breakthrough studies of how electrons speed around molecules in crucial processes in biology, chemistry, and materials science, among others.

The team says that until now, it was possible to observe the motions of atomic nuclei, but the much faster electron motions that drive the chemical reactions were blurred out. XLEAP will allow the X-ray laser to see how electrons move around and how that sets the stage for chemistry that follows. The team believes that studies on the timescales enabled by XLEAP could reveal things like how the absorption of light during photosynthesis almost instantaneously pushes electrons and starts the cascade of other events that result in oxygen generation.

Experiments showed that the XLEAP team can produce precisely timed pairs of attosecond X-ray pulses that can set electrons in motion and record those movements. The snapshots can be strung together to create stop-action movies. XLEAP is described as a great advance that gives scientists a breakthrough tool to observe and control electron motion at individual atomic sites in complex systems.

The team plans to further optimize their method, and that optimization could lead to more intense and possibly shorter pulses. The team is also getting ready for LCLS-II, the upgrade of their user system that can fire up to a million X-ray pulses per second, which is 8,000 times faster than before.