Correlation consistent auxiliary basis sets in density fitting Hartree-Fock: The atoms sodium through argon revisited

Area of Science:

• Computational chemistry
• Quantum chemistry

Background:

• Density-fitted Hartree-Fock (DF-HF) calculations are crucial for electronic structure.
• Auxiliary basis sets (ABS) are essential for efficient DF-HF.
• Existing ABS can have deficiencies when paired with correlation-consistent orbital basis sets.

Purpose of the Study:

• To develop and validate new auxiliary basis sets for elements Sodium (Na) to Argon (Ar).
• To improve the accuracy of DF-HF calculations using correlation-consistent (cc-pV(n+d)Z) orbital basis sets.
• To provide recommendations for pairing ABS with various orbital basis sets, including cc-pVnZ and cc-pVnZ-F12.

Main Methods:

• Development of new auxiliary basis sets for Na-Ar.
• Benchmarking calculations using total molecular energies, reaction energies, and spectroscopic constants.
• Evaluation of performance with cc-pV(n+d)Z and cc-pVnZ orbital basis sets.

Main Results:

• The newly developed auxiliary basis sets effectively address deficiencies of existing sets.
• Improved accuracy was demonstrated for molecular energies and spectroscopic constants (e.g., for the SO molecule).
• Auxiliary basis sets for Na and Mg compatible with cc-pVnZ were reported.

Conclusions:

• The new auxiliary basis sets significantly enhance the reliability of DF-HF calculations.
• These sets are recommended for use with cc-pV(n+d)Z orbital basis sets for accurate electronic structure studies.
• Recommendations are provided for optimal pairing of auxiliary basis sets with cc-pVnZ and cc-pVnZ-F12 basis sets.