Incorporating Nuclear Quantum Effects in Molecular Dynamics with a Constrained Minimized Energy Surface

Area of Science:

• Computational Chemistry
• Quantum Mechanics
• Molecular Dynamics

Background:

• Accurately simulating nuclear quantum effects in large-scale molecular dynamics (MD) is computationally challenging.
• Existing methods like centroid MD and ring-polymer MD have limitations in describing vibrations.

Purpose of the Study:

• To develop a novel theoretical framework for incorporating nuclear quantum effects into classical MD simulations.
• To provide a more accurate and efficient approach for molecular dynamics simulations.

Main Methods:

• Developed a new formulation of the equations of motion for MD based on constrained nuclear-electronic orbital (CNEO) theory.
• Quantum nuclear wave functions are solved via constrained energy minimization.
• Expectation values of quantum nuclear positions evolve classically on an effective energy surface.

Main Results:

• The new CNEO-MD approach accurately and efficiently incorporates nuclear quantum effects.
• Demonstrated significantly higher accuracy compared to conventional classical MD.
• Outperformed centroid MD and ring-polymer MD in describing vibrations in model systems.

Conclusions:

• CNEO-MD offers a robust theoretical foundation for including nuclear quantum effects in classical MD.
• This method provides a more accurate and efficient alternative for molecular simulations involving quantum nuclear behavior.