Ab initio molecular dynamics with nuclear quantum effects at classical cost: Ring polymer contraction for density...

Area of Science:

• Computational Chemistry
• Quantum Mechanics
• Materials Science

Background:

• Accurate simulation of light nuclei requires quantum mechanical treatment of electrons and nuclei.
• Traditional path integral simulations are computationally expensive, limiting their application.

Purpose of the Study:

• To develop a computationally efficient method for ab initio molecular dynamics (AIMD) that includes nuclear quantum effects.
• To reduce the cost of path integral simulations by extending the ring polymer contraction approach.

Main Methods:

• Extended ring polymer contraction to AIMD simulations.
• Utilized density functional tight binding (DFTB) as a reference system.
• Applied the method to liquid water and water dimer systems.

Main Results:

• Ring polymer contraction shows rapid convergence to full path integral results.
• Nuclear quantum effects are accurately captured by contracting to the ring polymer centroid.
• The developed approach achieves computational speeds comparable to classical AIMD.

Conclusions:

• A computationally feasible method for including nuclear quantum effects in AIMD simulations has been developed.
• This approach enables routine inclusion of nuclear quantum effects at negligible cost.
• The method accurately simulates systems with light nuclei, such as water.