Accurate Hybrid Density Functionals with UW12 Correlation.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Density Functional Theory

Background:

• Previous work introduced the single-parameter hybrid functional UW12, incorporating a novel correlation contribution based on the Unsöld approximation.
• This UW12 model mirrors the explicitly correlated component of MP2-F12 theory and is expressible via the single-particle reduced density matrix.

Purpose of the Study:

• To investigate hybrid functionals incorporating UW12 correlation, with a focus on reducing self-interaction error.
• To propose and evaluate new hybrid functionals, specifically B-LYP-osUW12 and fB-LYP-osUW12, designed for enhanced accuracy.

Main Methods:

• Development and testing of novel hybrid density functionals.
• Incorporation of the Unsöld approximation-based correlation contribution (UW12).
• Focus on functionals with a high percentage of exact exchange to mitigate self-interaction error.

Main Results:

• The proposed B-LYP-osUW12 functional demonstrates comparable accuracy to leading double hybrid functionals.
• This new functional achieves high accuracy without the computational requirement of virtual orbitals.
• Evaluation on established test sets confirms the performance of the developed functionals.

Conclusions:

• The B-LYP-osUW12 functional represents a significant advancement in computational chemistry, offering high accuracy and efficiency.
• The findings suggest that hybrid functionals with UW12 correlation and substantial exact exchange are promising for accurate electronic structure calculations.
• The elimination of the need for virtual orbitals in B-LYP-osUW12 offers a practical advantage for computational efficiency.