Efficient electronic structure calculation for molecular ionization dynamics at high x-ray intensity.

Area of Science:

• Computational Chemistry
• Atomic and Molecular Physics
• X-ray Science

Background:

• X-ray free-electron lasers (XFELs) enable unprecedented studies of molecular dynamics.
• Understanding molecular ionization dynamics under intense X-ray fields is crucial but computationally challenging.
• Existing methods struggle to accurately capture multiple ionization and subsequent nuclear motion.

Purpose of the Study:

• To implement and validate an electronic-structure approach for simulating molecular ionization dynamics with XFEL pulses.
• To efficiently calculate multiple ionization and core-hole states in molecules exposed to XFELs.
• To provide a tool for investigating complex chemical dynamics driven by intense X-ray interactions.

Main Methods:

• Utilized a linear combination of numerical atomic orbitals to represent molecular orbitals in core-hole states.
• Developed an electronic-structure scheme tailored for XFEL-matter interactions.
• Focused on accurately calculating all possible multiple-hole configurations.

Main Results:

• Successfully implemented an electronic-structure approach for XFEL-induced ionization dynamics.
• Demonstrated efficient calculation of multiple ionization states and configurations.
• The method accurately models molecular core-hole states using atomic orbital solutions.

Conclusions:

• The presented method is suitable for investigating x-ray multiphoton multiple ionization dynamics.
• It provides essential insights into accompanying nuclear dynamics and chemical changes.
• This computational tool is valuable for high-intensity X-ray imaging applications.