Communication: A novel implementation to compute MP2 correlation energies without basis set superposition errors and...

Area of Science:

• Computational Chemistry
• Quantum Mechanics
• Electronic Structure Theory

Background:

• Second-order Møller-Plesset perturbation (MP2) theory is a widely used method for calculating electron correlation.
• Traditional MP2 implementations often suffer from basis set superposition errors and require computationally expensive basis set extrapolation.
• Plane wave (PW) basis sets offer advantages but require specific handling for response properties.

Purpose of the Study:

• To develop a novel and efficient implementation of MP2 theory using a plane wave (PW) basis set.
• To overcome limitations of existing MP2 methods, such as basis set superposition errors and the need for complete basis set extrapolation.
• To accurately represent response functions and avoid summations over large numbers of virtual states.

Main Methods:

• Formulation based on dynamical polarizability.
• Utilization of plane wave (PW) basis sets.
• Employing eigenvectors of static polarizability as an auxiliary basis set.
• Formalism inspired by density functional perturbation theory to avoid summations over virtual states.
• Application of the Lanczos algorithm to incorporate dynamical effects.

Main Results:

• A novel MP2 implementation in a PW basis set that is free from basis set superposition errors.
• Converged results without requiring complete basis set extrapolation techniques.
• Efficient representation of response functions using an auxiliary basis set.
• Demonstrated accuracy through applications to three weakly interacting dimers.

Conclusions:

• The proposed method offers an accurate and efficient alternative for MP2 calculations.
• This approach eliminates common errors and computational burdens associated with traditional MP2 methods.
• The use of PW basis sets and novel techniques provides a robust framework for future electronic structure studies.