Attochemistry Regulation of Charge Migration

Area of Science:

• Physical Chemistry
• Quantum Chemistry
• Attosecond Science

Background:

• Charge migration (CM) describes coherent, attosecond-scale electron hole movement within molecules.
• Understanding CM dynamics is crucial for predicting molecular behavior after ionization.

Purpose of the Study:

• To investigate the relationship between molecular structure and charge migration dynamics.
• To explore how functional groups influence the charge migration process in bromobenzene derivatives.

Main Methods:

• Real-time time-dependent density functional theory (TD-DFT) was employed.
• Systematic studies were performed on para-functionalized bromobenzene molecules (X-C6H4-R).
• Valence-electron dynamics were initiated by emulating strong-field ionization, localizing a hole on bromine.

Main Results:

• Charge migration occurs on a femtosecond timescale via a localized hole delocalization-relocalization mechanism.
• The hole contrast on acceptor functional groups increases with electron-donating strength.
• This trend correlates well with Hammett σ values, quantifying substituent effects.

Conclusions:

• Attochemistry principles and density-based models can predict and explain charge migration dynamics.
• Molecular functionalization significantly impacts the pathway and extent of charge migration.
• The study provides insights into controlling ultrafast electron dynamics in molecules.