Complex Absorbing Potential Green's Function Methods for Resonances

Area of Science:

• Computational Chemistry
• Quantum Mechanics
• Theoretical Physics

Background:

• Complex Absorbing Potential (CAP) formalism is established for wave function methods studying electronic resonances.
• Green's function methods excel at ionization potentials/electron affinities but have limited resonance applications.

Purpose of the Study:

• To integrate the CAP formalism into the GW approximation for Green's function-based electronic resonance studies.
• To enable a comprehensive description of electronic resonances within a Green's function framework.

Main Methods:

• Implemented CAP formalism within the GW approximation (CAP-GW).
• Employed a fully complex treatment of orbitals and quasiparticle energies in a non-Hermitian setting.
• Validated the method on N2-, CO-, CO2-, C2H2-, C2H4-, and CH2O- shape resonances.

Main Results:

• Successfully described electronic resonances using the CAP-GW method.
• Achieved accuracy comparable to state-of-the-art wave function-based methods.
• Demonstrated a fast and practical route for approximating resonance lifetimes and positions.

Conclusions:

• The CAP-GW method offers a powerful new tool for studying electronic resonances.
• This approach expands the applicability of Green's function methods to resonance phenomena.
• The validated method provides reliable predictions for molecular resonance states.