Nonadiabatic Molecular Dynamics with Tight-Binding Fragment Molecular Orbitals

Area of Science:

• Computational Chemistry
• Materials Science
• Quantum Dynamics

Background:

• Modeling charge and energy transfer in large molecular systems is computationally demanding.
• Accurate simulations are crucial for understanding organic electronic devices.

Purpose of the Study:

• To develop an efficient nonadiabatic molecular dynamics methodology for large systems.
• To investigate charge transfer dynamics in organic heterojunctions.

Main Methods:

• Utilized fragment molecular orbitals (FMOs) with tight-binding Hamiltonians.
• Employed quantum-classical trajectory-based approaches.
• Developed a chemically motivated fragmentation scheme for arbitrary systems.

Main Results:

• Adiabatic FMOs proved most suitable for nonadiabatic dynamics.
• The method exhibits favorable scaling for large systems (hundreds of atoms).
• Simulations of SubPc/C60 heterojunctions highlighted the role of decoherence and interface structure.

Conclusions:

• The developed methodology enables long time-scale charge transfer simulations.
• Accurate modeling of charge transfer requires considering decoherence and interfacial details.
• This approach is valuable for designing organic electronic materials.