Ultrafast Optical Pump-Hard X-Ray Probe Spectroscopy of Transition Metal Complexes in Solution at SLAC.

Area of Science:

• Chemical Physics
• Materials Science
• Biophysics

Background:

• Time-resolved X-ray spectroscopy is crucial for understanding ultrafast dynamics in photoexcited systems.
• Such studies are vital for elucidating mechanisms in catalysis and biological processes.
• Synergistic use of synchrotron and X-ray free-electron laser facilities offers unique capabilities.

Purpose of the Study:

• To provide an update on solution-phase optical pump X-ray probe capabilities.
• To highlight the combined strengths of the Linac Coherent Light Source (LCLS) and Stanford Synchrotron Radiation Lightsource (SSRL).
• To showcase the characterization of transient states and dynamics in photoexcited systems.

Main Methods:

• Utilizing X-ray absorption, emission, and scattering techniques.
• Employing complementary X-ray probes spanning femtosecond (fs) to nanosecond (ns) timescales.
• Coordinated optical pump X-ray probe experiments at LCLS (XCS instrument) and SSRL (beamline 15-2).

Main Results:

• Demonstrated characterization of transient electronic states.
• Identified charge-transfer pathways in photoexcited systems.
• Revealed photoinduced structural rearrangements with high temporal resolution.

Conclusions:

• The colocation of LCLS and SSRL provides a powerful, synergistic platform for ultrafast X-ray studies.
• Coordinated multi-facility approaches enable comprehensive multiscale investigations of excited-state dynamics.
• These capabilities advance the understanding of fundamental processes in chemistry and biology.