Sub-picosecond X-ray pulse reveals atomic-scale dynamics

Projects involving international collaboration are currently under way at the Stanford Linear Accelerator Center, in the U.S., using very bright pulses of X-ray light one thousand times shorter than those typically produced in conventional synchrotron rings. One of the topics studied very recently concerns melting- how solids transform into liquids on ultra fast time scales. In the experiment, laser light was used to melt a crystal of InSb, and then ultra-short X-ray pulses were sent to probe the material. The scattered X-rays provided a glimpse of the first step in the transition from solid to liquid. It was found that the transition state is governed by inertial dynamics, simply stated by Newton's First Law as: an object in motion continues in motion. For more information, see the paper, "Atomic-Scale Visualization of Inertial Dynamics", A. M. Lindenberg et al., Science, 308, 392-395 (2005).