Ultraintense, ultrashort pulse X-ray scattering in small molecules

Area of Science:

• Atomic and Molecular Physics
• Chemical Physics
• X-ray Science

Background:

• Understanding molecular dynamics under intense X-ray fields is crucial for fields like attosecond science.
• X-ray scattering provides insights into molecular structure and electronic properties.
• Exploring the transition from linear to nonlinear X-ray-matter interactions is key to novel spectroscopic methods.

Purpose of the Study:

• To investigate X-ray scattering from isolated organic molecules across linear and nonlinear regimes.
• To analyze the roles of coherent and incoherent scattering channels in nonlinear interactions.
• To demonstrate the potential of coherent X-ray scattering for visualizing ultrafast molecular processes.

Main Methods:

• Examining X-ray scattering experiments on isolated organic molecules.
• Utilizing theoretical calculations including the independent atom model (IAM), Hartree-Fock (HF), and density functional theory (DFT).
• Analyzing nonlinear behavior as a function of X-ray pulse duration and energy.

Main Results:

• Observed the onset of nonlinear X-ray scattering behavior.
• Determined the significance of both coherent and incoherent scattering channels in the nonlinear regime.
• Calculations showed the sensitivity of linear scattering signals to molecular bonding and electronic correlation.
• Demonstrated the visualization of femtosecond charge transfer and dissociation using coherent X-ray scattering.

Conclusions:

• Coherent X-ray scattering is a powerful tool for probing ultrafast molecular dynamics.
• The study elucidates the interplay between coherent and incoherent scattering in nonlinear X-ray-matter interactions.
• This approach enables direct visualization of fundamental processes like charge transfer and dissociation in single molecules.