Advanced Photon Source

An Office of Science National User Facility

Atomic, Molecular and Optical Physics (AMO)

The AMO Physics program seeks quantitative understanding of x-ray interactions with atoms, molecules, and clusters from the weak-field limit explored at Argonne's Advanced Photon Source (APS) to the strong-field regime accessible at the Linac Coherent Light Source (LCLS) and other x-ray light sources around the world. We perform experimental and theoretical research on x-ray and inner-shell processes, pump/probe studies of molecular and chemical dynamics, and ultrafast x-ray diffractive imaging of nanometer-sized samples. Theory is a key element of our program by predicting phenomena that motivate experiments and by simulating measured results.  The AMO group is particularly active at APS beamline 7-ID where we use high-repetition-rate lasers for pump/probe measurements on the photodynamics of solvated molecules and x-ray/ion coincidence measurements on core-hole decay dynamics of gas-phase molecules.  The LCLS experiments are targeted at x-ray physics at the intensity frontier and the investigation of ultrafast inner-shell induced dynamcis. We employ the latest optical/x-ray and x-ray/x-ray pump/probe schemes to investigate in the high-intensity limit the dynamical processes in complex samples or to follow intramolecular dynamics on time-scales of electron motion. Theoretical studies include intense x-ray interactions with atoms, clusters, and nanoparticles utilizing the Mira supercomputer at the Argonne Leadership Computing Facility.  A selection of recent research projects is described in the Current Research section.