Quantum Molecular Charge-Transfer Model for Multistep Auger-Meitner Decay Cascade Dynamics

Area of Science:

• Atomic and Molecular Physics
• Chemical Physics
• Materials Science

Background:

• Inner-shell decay in heavy elements causes X-ray damage in materials and medical applications.
• Current simulations often neglect molecular bonding effects, focusing on atomic electronic structure.

Purpose of the Study:

• To develop a novel computational approach coupling Auger-Meitner decay with nuclear dynamics for multistep processes.
• To provide a continuous description of electron transfer and fragmentation dynamics during molecular decay cascades.

Main Methods:

• Developed a decay spawning dynamics algorithm.
• Applied the algorithm to potential energy surfaces from ab initio molecular dynamics simulations.
• Modeled K-shell ionization and Kβ fluorescence decay in IBr.

Main Results:

• Simulated two competing decay channels in IBr, leading to 3+ charged ion pairs.
• Revealed a combined inner-shell decay and charge transfer timescale of approximately 75 fs.
• Computed ion fragment kinetic energies that align well with experimental data.

Conclusions:

• The novel approach accurately describes multistep decay cascades and molecular fragmentation.
• This method enhances understanding of X-ray damage mechanisms in heavy-element containing molecules.
• Findings have implications for advanced materials characterization and radionuclide therapy.