Charge-constrained auxiliary-density-matrix methods for the Hartree-Fock exchange contribution

Area of Science:

• Computational chemistry
• Quantum chemistry
• Electronic structure theory

Background:

• The auxiliary-density-matrix method (ADMM) is a computational technique used in quantum chemistry.
• Previous ADMM methods, like ADMM1, required full orthonormality, which can be computationally demanding.

Purpose of the Study:

• To introduce and evaluate three new variants of the auxiliary-density-matrix method (ADMM).
• To assess the accuracy and performance of these new ADMM variants in all-electron calculations.
• To investigate the impact of different exchange functionals on the ADMM exchange-correction term.

Main Methods:

• Development of three new ADMM variants with simplified constraints.
• Testing the variants using all-electron B3LYP calculations.
• Employing several standard basis sets for the calculations.
• Analyzing the influence of various exchange functionals on the ADMM exchange-correction.

Main Results:

• The new ADMM variants demonstrate comparable accuracy to earlier methods but with simplified constraints.
• Performance evaluations show efficiency gains in all-electron B3LYP calculations across different basis sets.
• The choice of exchange functional significantly affects the ADMM exchange-correction term's accuracy.

Conclusions:

• The presented ADMM variants offer a computationally efficient alternative to existing methods.
• These simplified ADMM approaches maintain high accuracy in electronic structure calculations.
• Further investigation into exchange functional selection can optimize ADMM performance.