CPM Seminar

Measuring transient structure with ultrafast x rays

David Reis

Stanford University & PULSE Institute

Last year the first hard x-ray free electron laser, the Linac Coherent Light Source (LCLS), began operating at the SLAC National Accelerator Laboratory on Stanford campus. This powerful new source of short- pulse and coherent x rays is orders of magnitude brighter than any other synchrotron source. The high intensity short pulses from the LCLS is enabling access to fundamentally different regimes of physics, from nonlinear x-ray science and the physics of multiply core-hole excited atoms and molecules, to coherent imaging of nanoparticles and potentially even single molecules, to the probing of structure and dynamics on with unprecedented resolution in time and space. In this talk, I will discuss our efforts to use x rays to image nonequilbrium dynamics in photoexcited solids, including relaxation of hot carriers and phonons and the evolution of excited- state interatomic potentials in highly excited systems. I will also give a brief overview of the LCLS, how we hope to make use of its remarkable properties, and a taste of some initial results.