Revised Basis Sets for the LANL Effective Core Potentials.

Area of Science:

• Computational chemistry
• Quantum chemistry
• Materials science

Background:

• Relativistic effective core potentials (RECPs) are crucial for accurate electronic structure calculations.
• Existing basis set contractions, like double-ζ, may not be optimal for modern computational methods such as DFT.
• Hay-Wadt RECPs are widely used but require optimized basis sets for enhanced performance.

Purpose of the Study:

• To develop and propose new, contracted basis sets for Hay-Wadt RECPs.
• To improve the suitability of basis sets for density functional theory (DFT) investigations.
• To provide basis sets that are effective for both DFT and wave function-based methods.

Main Methods:

• Contraction of original Hay-Wadt primitive functions for transition metal atoms.
• Development of new basis set notations: LANL2TZ for transition metals and LANL08 for main group atoms.
• Advocating for uncontracted basis sets for main group elements in the LANL08 designation.

Main Results:

• The proposed LANL2TZ basis sets offer optimized contractions ([5s5p3d], [4s4p3d], [4s4p3d]) for the first, second, and third transition series.
• The LANL08 basis sets are recommended for main group atoms, providing a robust option.
• These new basis sets demonstrate improved suitability for DFT calculations compared to previous contractions.

Conclusions:

• The new LANL2TZ and LANL08 basis sets represent an advancement in computational chemistry.
• These basis sets are well-suited for DFT and wave function-based studies of molecules and materials.
• Supplementing transition metal basis sets with Frenking's polarization functions is suggested for further refinement.