Ab Initio Molecular Dynamics of Temporary Anions Using Complex Absorbing Potentials

Area of Science:

• Chemical Physics
• Theoretical Chemistry
• Computational Chemistry

Background:

• Dissociative electron attachment (DEA) is challenging for standard quantum-chemical methods due to unstable anion intermediates.
• Temporary anions are short-lived and prone to autodetachment, complicating dynamic simulations.
• Accurate modeling of DEA requires methods that can handle unbound anionic states.

Purpose of the Study:

• To develop a novel computational approach for simulating the dynamics of temporary anions in DEA.
• To accurately model the behavior of transient negative ions undergoing bond cleavage.
• To provide mechanistic insights into DEA processes for various molecules.

Main Methods:

• Utilizing complex-valued potential energy surfaces to describe electron loss and nuclear forces.
• Employing an analytical force computation based on Hartree-Fock theory.
• Incorporating a complex absorbing potential to model electron detachment.
• Performing *ab initio* molecular dynamics simulations.

Main Results:

• The new method successfully simulates the dynamics of temporary anions on complex-valued potential energy surfaces.
• Simulations show qualitative agreement with experimental observations for various molecules.
• Mechanistic insights into DEA were gained for dinitrogen, ethylene, chloroethane, and chlorinated ethylenes.
• The method effectively handles both dissociative and auto-detaching temporary anions.

Conclusions:

• The developed computational method provides a robust framework for studying dissociative electron attachment.
• This approach offers a more accurate and versatile tool for understanding electron-molecule interactions.
• The findings advance the theoretical modeling capabilities for chemical reactions initiated by low-energy electrons.