Exploiting Coordinate Scaling Relations To Accelerate Exact Exchange Calculations.

Area of Science:

• Computational Chemistry
• Materials Science
• Quantum Mechanics

Background:

• Exact exchange is crucial for accurate exchange-correlation (xc) functionals in Kohn-Sham Density Functional Theory (DFT).
• Evaluating exact exchange is computationally expensive, limiting its use in DFT-based molecular dynamics (MD) simulations, which often employ less accurate semilocal functionals.

Purpose of the Study:

• To derive and implement a computationally efficient scheme for evaluating exact exchange energy and potential.
• To accelerate first-principles molecular dynamics (MD) simulations that utilize hybrid functionals.

Main Methods:

• Developed a novel scheme based on the formal coordinate scaling properties of the exact xc functional.
• Implemented the scheme within a plane-wave/pseudopotential framework for DFT calculations.
• Tested the method's accuracy and performance in MD simulations.

Main Results:

• Achieved substantial reductions in the computational cost of exact exchange evaluation.
• Retained excellent accuracy compared to standard methods.
• Observed speed-ups of up to approximately 6 times for exact exchange calculations.
• Accelerated hybrid-functional-based first-principles MD simulations by nearly one order of magnitude.

Conclusions:

• The coordinate scaling approach offers a significant computational advantage for including exact exchange in DFT.
• This method enables more extensive and accurate first-principles MD simulations using hybrid functionals.
• The developed scheme is a valuable tool for advancing computational materials science and chemistry research.