Stochastic stimulated electronic x-ray Raman spectroscopy.

Area of Science:

• Atomic and Molecular Physics
• Chemical Physics
• Condensed Matter Physics

Background:

• Resonant inelastic x-ray scattering (RIXS) is crucial for studying dynamics in matter.
• Current time-resolved RIXS at X-ray Free Electron Lasers (XFELs) faces challenges with low signal rates due to monochromator use.
• Studying ultrafast chemical and structural changes on femtosecond timescales requires advanced spectroscopic techniques.

Purpose of the Study:

• To propose and validate a novel approach for time-resolved RIXS at XFELs.
• To overcome the limitations of conventional RIXS implementations at XFELs.
• To enable high-resolution studies of ultrafast molecular dynamics.

Main Methods:

• Utilizing stochastic spectroscopy with the full bandwidth of XFEL pulses.
• Employing stimulated resonant inelastic x-ray scattering (SRIXS) with pump and seeded probe pulses.
• Applying covariance analysis of transmitted spectra for high-resolution spectral data.
• Developing a theoretical model to simulate spectral and temporal evolution of x-ray radiation.

Main Results:

• Demonstrated feasibility of SRIXS for high-resolution spectroscopy at XFELs.
• Predicted achievable signal strengths for realistic XFEL parameters.
• Modeled the dynamics of the CO molecule pumped at the C 1s transition.
• Showcased the capability to obtain high-resolution RIXS spectra via covariance analysis.

Conclusions:

• The proposed stochastic spectroscopy method offers a viable alternative for time-resolved RIXS at XFELs.
• This technique enhances signal rates and enables femtosecond-scale studies of molecular dynamics.
• SRIXS with covariance analysis provides a pathway to high-resolution spectral data, advancing ultrafast science.