Low-scaling first-order properties within second-order Møller-Plesset perturbation theory using Cholesky decomposed...

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Theoretical Chemistry

Background:

• Second-order Møller-Plesset perturbation theory (MP2) is a cornerstone for accurate electronic structure calculations.
• Calculating energy gradients and hyperfine coupling constants is crucial for understanding molecular properties and reactivity.
• Existing methods can be computationally expensive, limiting their application to larger systems.

Purpose of the Study:

• To develop an efficient, fully atomic orbital (AO)-based implementation for MP2 energy gradients and hyperfine coupling constants.
• To reduce the computational cost and improve the scalability of these important molecular properties calculations.
• To introduce an unrestricted AO-based MP2 formulation for broader applicability.

Main Methods:

• Implementation of energy gradients and hyperfine coupling constants within a fully AO-based MP2 framework.
• Utilized Cholesky decomposition to reduce basis set dependency and resolution-of-the-identity approximation to lower prefactors.
• Employed distance-including integral estimates (QQR-screening) for efficient selection of significant integral contributions.
• Demonstrated the reliability of QQR-screening as a controlled procedure.

Main Results:

• Achieved a reduction in computational efficiency dependency on basis set size.
• Demonstrated cubic scaling for energy gradients and quadratic scaling for hyperfine coupling constants calculations.
• Showcased significant speed-up compared to the canonical MP2 formulation.
• Validated the reliability and controlled nature of the QQR-screening procedure.

Conclusions:

• The developed AO-based MP2 approach offers a computationally efficient and scalable method for calculating energy gradients and hyperfine coupling constants.
• This advancement enables more accurate theoretical investigations of molecular properties for larger systems.
• The implementation provides a valuable tool for theoretical and computational chemists.