Berkeley Lab


The Chemical Dynamics Project employs a variety of femtosecond and picosecond XUV and X-ray light sources to study electronic and structural dynamics in molecules, clusters, and interfacial systems. Laboratory-based experiments using high-order harmonics generation (HHG) driven light sources are complemented by experimental campaigns at X-ray free electron lasers (X-FELs) and synchrotron radiation light sources.

HHG based experiments

All laboratory based experiments of the Chemical Dynamics Project are driven by a high-power, high-repetition rate femtosecond laser system operating at a central wavelength of 780 nm that runs at repetition rate of 1-3 kHz with up to 12-15 W average power output (≤12 mJ at 1 kHz, ≤5 mJ at 3 kHz), and a pulse duration of ≈25 fs. This laser drives three high-order harmonic generation light sources consisting of gas cells filled with noble gases at pressures of several to several 10 mbar. The emerging femtosecond XUV and X-ray pulses are used to either access highly excited states of noble gas clusters or probe ultrafast molecular dynamics by time-resolved inner-shell absorption spectroscopy.

Figure A1: Schematic of the femtosecond XUV photoelectron and ion imaging experiment that is used to study ultrafast dynamics in superfluid helium nanodroplets.



Figure A2. Components of the Chemical Dynamics experimental setup:

Figure A2

a) High repetition rate, high power femtosecond laser system


Figure A2 b)

b) femtosecond HHG beamline



c) panorama of Chemical Dynamics Laboratory

X-FELs and Synchrotrons

Femtosecond and picosecond time-resolved X-ray spectroscopy and coherent diffractive imaging experiments are currently performed at the Linac Coherent Light Source (LCLS) X-ray free electron laser (X-FEL) at SLAC National Accelerator Laboratory and the Advanced Light Source (ALS) synchrotron radiation facility at Berkeley Lab.