Electron transfer pathways from quantum dynamics simulations.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Biophysical Chemistry

Background:

• Electron transfer is fundamental in biological and chemical processes.
• Accurately simulating real-time electron transfer dynamics remains a challenge.
• Defining non-equilibrium initial states is crucial for triggering charge transfer.

Purpose of the Study:

• To explore real-time electron transfer simulation using time-dependent density functional theory (TD-DFT) electron dynamics.
• To propose and validate two novel schemes for preparing non-equilibrium initial states.
• To investigate electron transfer pathways in complex biological systems.

Main Methods:

• Time-dependent density functional theory (TD-DFT) electron dynamics.
• Two initial state preparation schemes: density matrix combination and constrained DFT.
• Hybrid Quantum Mechanics/Molecular Mechanics (QM/MM) framework.

Main Results:

• Successfully simulated electron transfer in atomic hydrogen dimer, polyacetylene chain, and T. cruzi heme peroxidase active site.
• Established relative probabilities of two postulated electron transfer paths in the enzyme.
• Provided insights into electron transfer inhibition by specific mutations (W233F).

Conclusions:

• The developed TD-DFT electron dynamics approach with novel initial state preparation is effective for simulating electron transfer.
• The methodology can elucidate reaction mechanisms and the impact of mutations in biological systems.
• This work offers a valuable computational tool for studying charge transfer dynamics.