Correlation consistent basis sets for explicitly correlated wavefunctions: Pseudopotential-based basis sets for the...

Area of Science:

• Computational chemistry
• Quantum chemistry
• Basis set development

Background:

• Explicitly correlated F12 methods significantly reduce the basis set incompleteness error.
• Developing efficient and accurate basis sets is crucial for computational chemistry, especially for heavy elements.

Purpose of the Study:

• To develop new correlation consistent basis sets for group 11 (Cu, Ag, Au) and 12 (Zn, Cd, Hg) elements.
• These basis sets are specifically designed for explicitly correlated F12 calculations.

Main Methods:

• Developed valence-only (cc-pVnZ-PP-F12) and outer core-valence (cc-pCVnZ-PP-F12) basis sets.
• Augmented basis sets with high angular momentum diffuse functions.
• Optimized matching auxiliary basis sets for density fitting and resolution-of-the-identity methods.
• Utilized small-core relativistic pseudopotentials.

Main Results:

• Benchmark calculations at the explicitly correlated coupled-cluster level assessed accuracy.
• Demonstrated dramatically improved convergence compared to conventional coupled-cluster calculations.
• Achieved results close to the complete basis set limit with cc-pVTZ-PP-F12 basis sets.

Conclusions:

• The new basis sets significantly enhance the efficiency and accuracy of F12 calculations for heavy elements.
• Improved convergence patterns were observed compared to conventional basis sets in F12 calculations.
• These developments offer a more reliable approach for studying properties of group 11 and 12 elements.