Communication: Compact orbitals enable low-cost linear-scaling ab initio molecular dynamics for weakly-interacting...

Area of Science:

• Computational Chemistry
• Materials Science
• Quantum Mechanics

Background:

• Ab initio molecular dynamics (AIMD) typically uses density matrices for linear scaling.
• Localizing one-electron density matrices is key to computational efficiency in large systems.
• Compact Kohn-Sham orbitals offer potential advantages but are challenging to implement in AIMD.

Purpose of the Study:

• To develop a method for stable nuclear dynamics using compact orbitals in AIMD.
• To eliminate the need for density matrix optimization in AIMD.
• To enable first orbital-only linear-scaling AIMD for enhanced computational efficiency.

Main Methods:

• Coupling a robust method for compact orbitals with a modified Langevin integrator.
• Implementing an orbital-only approach to bypass density matrix optimization.
• Utilizing linear-scaling computational complexity for large-scale simulations.

Main Results:

• Achieved stable nuclear dynamics for molecular and ionic systems.
• Demonstrated the feasibility of first orbital-only linear-scaling AIMD.
• Showcased low computational overhead suitable for routine simulations.

Conclusions:

• The new orbital-only AIMD method significantly reduces computational cost.
• This approach enables first-principle studies on previously inaccessible length scales.
• The method is ideal for medium-scale simulations and exploring new physical phenomena.