Argonne National Laboratory

Atomic, Molecular, and Optical Physics

Atomic, Molecular, and Optical Physics

The AMO physics group explores the frontiers of X-ray science and lays the foundation of X-ray applications in other science domains.

The AMO Physics program seeks to understand quantitatively the interactions between atoms, molecules, and clusters. These interactions are explored from the weak-field limit available 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. We incorporate theory as 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 have developed high-repetition-rate methodologies for optical pump/X-ray probe measurements on laser-induced dynamics in isolated molecules, for example spin-crossover and photoswitching.  We also have introduced X-ray/ion coincidence measurements to track core-hole decay dynamics of gas-phase molecules.  Measurements of these dynamics are complemented by studies at shorter time scales at free-electron lasers.

Experiments at free-electron laser sources, primarily LCLS, are targeted at X-ray physics at the intensity frontier and the investigation of ultrafast inner-shell induced dynamics. We employ the latest optical/X-ray and X-ray/X-ray pump/probe schemes to investigate the dynamical processes in complex samples or to follow intramolecular dynamics on time scales of electron motion.

Theoretical studies include Monte Carlo/molecular dynamics modeling of intense X-ray interactions with atoms, clusters, and nanoparticles utilizing the Mira supercomputer at the Argonne Leadership Computing Facility.