Predicting Complete Basis Set Limit Quasiparticle Energies from Triple-ζ Calculations.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Materials Science

Background:

• Basis set incompleteness errors (BSIEs) are significant in GW calculations.
• Accurate prediction of quasi-particle (QP) energies is crucial for electronic structure.
• Existing extrapolation methods can be computationally expensive or inaccurate.

Purpose of the Study:

• To develop a simple linear model for estimating BSIEs in GW QP energies.
• To enable accurate extrapolation of QP energies to the complete basis set (CBS) limit.
• To provide a computationally efficient alternative to traditional extrapolation techniques.

Main Methods:

• A linear model was developed using orbital kinetic energy to predict BSIEs.
• The model was parametrized for G0W0, qsGW, and vertex-corrected GW methods.
• Reference CBS limit values were obtained using extensive correlation-consistent basis sets (TZ/6Z) for molecules with 10 elements.

Main Results:

• The developed model achieves BSIE extrapolation to the CBS limit with 20-30 meV accuracy for Gaussian- and Slater-type orbital basis sets.
• The model allows extrapolation from triple-zeta (TZ) basis sets.
• The commonly used inverse linear extrapolation method was found to produce larger errors unless a quadruple-zeta calculation is included.

Conclusions:

• A simple linear model effectively estimates BSIEs for GW QP energies.
• The model provides accurate CBS extrapolation, particularly useful for Gaussian- and Slater-type orbital basis sets.
• This approach offers a more accurate and efficient way to obtain reliable QP energies compared to standard extrapolation methods.