Extended Lagrangian molecular dynamics on vibronic surfaces in the nuclear-electronic orbital framework

Area of Science:

• Quantum Chemistry
• Chemical Dynamics
• Computational Chemistry

Background:

• Proton transfer is crucial in many chemical processes.
• Simulating proton transfer requires accounting for nuclear quantum effects like tunneling and zero-point energy.
• Existing methods may not fully capture these quantum mechanical aspects.

Purpose of the Study:

• Introduce novel simulation methods within the nuclear-electronic orbital (NEO) framework for proton transfer dynamics.
• Incorporate nuclear quantum effects, such as quantum proton treatment, into molecular dynamics simulations.
• Enhance the efficiency and accuracy of simulating complex proton transfer systems.

Main Methods:

• Utilize nuclear-electronic orbital density functional theory (NEO-DFT) to treat protons quantum mechanically.
• Formulate a NEO extended Lagrangian molecular dynamics (NEO-ELMD) approach.
• Implement density matrix extrapolation and purification to accelerate the NEO self-consistent field procedure.

Main Results:

• Demonstrated the fidelity and efficiency of the NEO-ELMD method for intramolecular proton transfer in malonaldehyde.
• Successfully simulated nonequilibrium single and double proton transfer dynamics in larger benzimidazole-phenol systems.
• Validated the accelerated techniques for efficient proton transfer simulations.

Conclusions:

• The developed NEO-ELMD approach provides a robust foundation for simulating proton transfer dynamics.
• The accelerated techniques significantly improve the efficiency of NEO-DFT calculations.
• This work enables future methodologies for simulating proton transfer with nonadiabatic effects.