Basis-set correction for coupled-cluster estimation of dipole moments

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Theoretical Chemistry

Background:

• Basis-set convergence is crucial for accurate molecular property calculations in wave-function theory (WFT).
• Previous methods for density-functional theory (DFT)-based basis-set correction were limited to ground-state energies or variational wave functions.
• Accurate computation of molecular properties like dipole moments is essential in various chemical applications.

Purpose of the Study:

• To develop and validate a general DFT-based approach for accelerating basis-set convergence of energy derivatives in non-variational WFT methods.
• To apply this correction to the calculation of dipole moments using coupled-cluster with single, double, and perturbative triple excitations (CCSD(T)).
• To assess the computational cost and accuracy improvement of the proposed method.

Main Methods:

• A novel DFT-based basis-set correction approach is proposed.
• The method is applied to calculate dipole moments using coupled-cluster with single, double, and perturbative triple excitations (CCSD(T)).
• The approach relies on Hartree-Fock densities, ensuring minimal additional computational cost.

Main Results:

• The proposed method successfully accelerates the basis-set convergence for dipole moment calculations.
• Numerical tests on 14 molecules demonstrate significant improvement compared to standard CCSD(T) calculations.
• The computational overhead of the basis-set correction is negligible.

Conclusions:

• The developed DFT-based basis-set correction offers an efficient way to improve the accuracy of molecular property calculations in WFT.
• This approach generalizes and extends previous correction methods.
• The method provides a computationally inexpensive yet effective route to achieve highly converged results for dipole moments.