Pseudodiagonalization-based wavefunction optimization with contracted planewave basis functions

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Materials Science

Background:

• Electronic structure calculations are crucial for understanding molecular properties.
• Contracted planewave basis functions (CPWBFs) offer an alternative to traditional basis sets.
• Existing methods for CPWBFs can be computationally intensive, especially for large systems.

Purpose of the Study:

• To develop and report methodological advances for optimizing wavefunctions using CPWBFs.
• To enable efficient electronic structure calculations with CPWBFs.
• To investigate the performance of CPWBF-based methods with hybrid exchange-correlation functionals.

Main Methods:

• Developed an FC_o-based wavefunction optimization technique.
• Combined pseudodiagonalization, approximate virtual orbital energies, and iterative subspace optimization.
• Utilized density functional theory (DFT) calculations.

Main Results:

• Achieved wavefunction optimization speed-ups of approximately 6-8 times compared to traditional Fock matrix (F)-based methods.
• Demonstrated that computational cost is relatively insensitive to basis set size.
• Enabled the use of hybrid exchange-correlation (XC) functionals with only a small increase in computational effort.

Conclusions:

• The reported FC_o-based optimization method significantly enhances the efficiency of electronic structure calculations using CPWBFs.
• This approach provides substantial computational benefits for large basis sets and complex molecular systems.
• The method facilitates the application of advanced DFT functionals in CPWBF calculations.