Modeling Intermolecular Coulombic Decay with Non-Hermitian Real-Time Time-Dependent Density Functional Theory

Area of Science:

• Quantum Chemistry
• Computational Physics
• Molecular Dynamics

Background:

• Inner-valence electron ionization can trigger complex electronic relaxation processes.
• Intermolecular Coulombic Decay (ICD) is a key relaxation pathway in noncovalently bonded systems.
• Accurate simulation of ICD dynamics is crucial for understanding molecular electronic behavior.

Purpose of the Study:

• To evaluate the efficacy of real-time time-dependent density functional theory (RT-TDDFT) coupled with a complex absorbing potential (CAP) for simulating ICD.
• To investigate ICD dynamics in hydrogen-bonded and van der Waals (VdW) dimer systems.
• To assess the accuracy of the RT-TDDFT/CAP methodology across different types of noncovalent interactions.

Main Methods:

• Implementation of RT-TDDFT combined with a CAP.
• Simulation of ICD processes in various noncovalent dimer systems.
• Analysis of electronic relaxation timescales and pathways.

Main Results:

• RT-TDDFT/CAP successfully captures ICD in systems with strong binding energies.
• Calculated ICD timescales range from 5-50 fs, consistent with prior research.
• The methodology shows limitations in accuracy for purely VdW-bonded systems.

Conclusions:

• The RT-TDDFT/CAP approach is a powerful tool for studying electronic relaxation after ionization.
• This method can differentiate competing relaxation pathways without prior assumptions.
• Further refinement may be needed for accurate simulations of ICD in weak VdW systems.