Attenuated second-order Møller-Plesset perturbation theory: performance within the aug-cc-pVTZ basis

Area of Science:

• Computational chemistry
• Quantum chemistry
• Theoretical chemistry

Background:

• Standard second-order Møller-Plesset perturbation theory (MP2) often overestimates dispersion interactions and suffers from basis set superposition error (BSSE) in finite basis sets.
• Accurate calculation of inter- and intra-molecular non-bonded interactions is crucial for understanding chemical systems.

Purpose of the Study:

• To develop and validate an attenuated MP2 method using a finite aug-cc-pVTZ (aTZ) basis set for improved accuracy in molecular interaction calculations.
• To assess the transferability and performance of the developed method across various molecular systems.

Main Methods:

• Development of an attenuated MP2 method with a single optimization parameter, denoted as MP2(terfc, aTZ).
• Optimization of the attenuation parameter using the S66 database of intermolecular interactions.
• Validation of the method on diverse datasets including S22, peptide/alkane/sugar conformers, sulfate-water clusters, and the coronene dimer.

Main Results:

• The attenuated MP2/aTZ method (MP2(terfc, aTZ)) achieved a >5-fold reduction in root-mean-square (RMS) error compared to standard MP2/aTZ.
• Attenuation was found to introduce an error of opposite sign to BSSE and overestimation of dispersion.
• MP2(terfc, aTZ) demonstrated good transferability to various inter- and intra-molecular interactions, often outperforming MP2 at the complete basis set limit.
• MP2(terfc, aTZ) generally outperformed MP2(terfc, aDZ), despite higher computational cost.

Conclusions:

• The developed attenuated MP2 method with a finite aug-cc-pVTZ basis set offers a computationally efficient and accurate approach for non-bonded interactions.
• The error cancellation mechanism in attenuated MP2 models provides a pathway to achieve results comparable to or better than complete basis set limit calculations.
• This method represents a significant advancement for theoretical studies of molecular interactions.