Strong field ionization rates simulated with time-dependent configuration interaction and an absorbing potential

Area of Science:

• Quantum Chemistry
• Computational Physics
• Molecular Dynamics

Background:

• Accurate modeling of molecular ionization is crucial for understanding chemical reactions and material properties.
• Existing methods like grid-based calculations are computationally intensive and limited in scope.
• Time-dependent configuration interaction (TDCI) offers a potential alternative for simulating electron dynamics.

Purpose of the Study:

• To develop and validate a novel computational approach for modeling molecular ionization rates.
• To investigate the phenomenon of charge resonance enhanced ionization (CREI) in various molecular systems.
• To demonstrate the applicability of the TDCI method to multi-electron polyatomic molecules.

Main Methods:

• Utilized time-dependent configuration interaction (TDCI) simulations.
• Employed atom-centered basis sets and a complex absorbing potential (CAP).
• Validated results against accurate grid-based calculations for atomic hydrogen and H2(+).

Main Results:

• Simulations accurately reproduced ionization rates of hydrogen atoms as a function of field strength.
• The method successfully modeled charge resonance enhanced ionization (CREI) in H2(+) as the bond elongated.
• Calculations on polyatomic ions (HCl(+) and HCO(+)) revealed CREI during bond stretching, demonstrating the method's capability for complex systems.

Conclusions:

• The TDCI approach with CAP provides an accurate and versatile tool for simulating molecular ionization.
• This method overcomes limitations of grid-based approaches, enabling studies of electron dynamics in complex molecules.
• The findings confirm the occurrence of CREI in various molecular ions, offering insights into their ionization mechanisms.