Atomic, Molecular and Optical Science Instrument

Intense short pulses of X-ray radiation created by the LCLS free electron laser (FEL) will interact with electrons in the sample being illuminated to create states of matter that have not been observed previously. The goal of the Atomic, Molecular and Optical (AMO) science instrumentation at the LCLS is to explore the interaction of this intense radiation with the simplest forms of matter, namely atoms and molecules, to gain an understanding of how their electronic structure responds. Femtosecond X-ray pulses from the LCLS also offer the opportunity to follow the evolution of chemical reactions on their natural time scales using well established and powerful tools such as ion, photoelectron, Auger and X-ray emission spectroscopy. A suite of instrumentation including focusing optics, gas delivery systems, electron, ion and photon spectrometers and a synchronized high-power laser are currently being designed for the AMO end-station.

Near Experimental Hall, Hutch 1 » complete instrument map

The interaction of ionizing radiation with matter has been a topic of much study since Hertz observed (1887) and Einstein described (1905) the photoelectric effect. While the mechanisms of excitation and ionization following the illumination of a sample with a weak beam of X-rays are well understood, little is known about the processes which occur when an intense beam of X-ray radiation strikes a target. Novel multi-electron processes are expected to occur and states of matter never before seen created. The goal of the AMO instrument is to study the interaction of the intense, short pulses of X-rays from the LCLS with the simplest forms of matter; atoms, molecules and clusters, to expand the understanding of which processes are important at different intensity regimes.

The extremely short pulses of X-rays from the LCLS provide a unique capability to study chemical processes at their natural time-scale. X-rays, such as those produced by the LCLS, interact with electrons in matter, exciting or ionizing them or scattering from them. Electron dynamics occur on the attosecond time-scale, much faster than the duration of the LCLS pulse. Nuclear dynamics (the motion of nuclei in a molecule) occur on the femtosecond time scales, however, a time scale that the LCLS is ideally suited to study, and the electronic structure of a molecule adjusts to the changing nuclear structure. Furthermore, photoionization of inner-shell electrons provide a site-specific probe of the electronic structure of a molecule, i.e. allowing electrons from a carbon atom to be differentiated from those of an oxygen atom. The LCLS is therefore a powerful tool for studying the motion of atoms in molecules reactions initiated by an external trigger (i.e., laser).

• Investigate multiphoton and high-field X-ray processes in atoms, molecules and clusters
  • Multi-photon ionization/excitation in atoms/molecules/clusters
  • Accessible intensity on verge of high-field regime
• Study time-resolved phenomena in atoms, molecules and clusters using ultrafast X-rays
  • Inner-shell side band experiments
  • Photoionization of aligned molecules
  • Temporal evolution of state-prepared systems