Probing basis set requirements for calculating hyperfine coupling constants.

Area of Science:

• Computational Chemistry
• Quantum Chemistry

Background:

• Accurate calculation of hyperfine coupling constants (HFCs) is crucial in various chemical and physical studies.
• Existing basis sets often exhibit slow convergence and significant errors, limiting computational accuracy.

Purpose of the Study:

• To introduce a new series of basis sets, termed pcH-n, specifically optimized for HFC calculations.
• To evaluate the performance of these basis sets in terms of convergence and accuracy compared to existing sets.

Main Methods:

• Development of pcH-n basis sets from polarization consistent (pc) sets by adding specific tight functions.
• Systematic testing of pcH-n basis sets for elements H to Ar across different cardinalities (double-ζ to pentuple-ζ).
• Assessment of basis set convergence and errors using density functional theory (DFT) and potentially wave function-based methods.

Main Results:

• The pcH-n basis sets demonstrate exponential convergence towards the complete basis set limit.
• These sets exhibit substantially reduced basis set errors compared to commonly used basis sets for equivalent cardinalities.
• The pcH-n basis sets show consistent convergence behavior across various DFT methods.

Conclusions:

• The proposed pcH-n basis sets provide a significant improvement in accuracy and efficiency for HFC calculations.
• These basis sets are recommended for computational chemistry studies requiring precise hyperfine coupling constant values.
• The pcH-n sets offer a reliable choice for both DFT and wave function-based computational approaches.