An efficient density-functional-theory force evaluation for large molecular systems.

Area of Science:

• Computational chemistry
• Materials science
• Quantum mechanics

Background:

• Kohn-Sham density-functional theory (KS-DFT) is a powerful tool for electronic structure calculations.
• Calculating molecular forces is crucial for geometry optimization and molecular dynamics.
• Traditional KS-DFT methods scale poorly with system size, limiting their application to large systems.

Purpose of the Study:

• To develop an efficient, linear-scaling implementation of KS-DFT for calculating molecular forces.
• To enable accurate simulations of molecular systems containing hundreds of atoms.

Main Methods:

• Linear-scaling implementation of Kohn-Sham density-functional theory.
• Density-fitted Coulomb force calculation using atomic integral screening and the continuous fast multipole method.
• Expansion of Gaussian basis functions in Hermite Gaussians for efficient near-field force calculation.

Main Results:

• Demonstration of efficiency and linear complexity in molecular force evaluation.
• Successful application to geometry optimization of large molecular systems.
• Significant speedup in computational time for large-scale simulations.

Conclusions:

• The presented method offers an efficient and scalable approach for molecular force calculations in large systems.
• This advancement facilitates accurate computational studies of complex molecular structures and properties.
• The method enhances the applicability of KS-DFT to industrially relevant system sizes.