Fast and Reliable Evaluation of Intermolecular Interactions with Second-Order Møller-Plesset Perturbation Theory and...

Area of Science:

• Computational chemistry
• Quantum chemistry
• Theoretical chemistry

Background:

• Accurate evaluation of noncovalent interactions is crucial in computational chemistry.
• Existing methods like second-order Møller-Plesset (MP2) can be computationally demanding and require basis set optimization.
• Density functional theory (DFT) has seen success with double-hybrid functionals, inspiring new approaches.

Purpose of the Study:

• To develop a new, ab initio basis set for improving the performance of the MP2 approach in calculating noncovalent interactions.
• To ensure the new basis set does not require specific parametrization, preserving the ab initio nature of MP2.
• To validate the transferability and robustness of the developed basis set across various molecular systems.

Main Methods:

• A novel basis set, termed MP-SVP, was derived using a self-consistent formula.
• The optimization involved adjusting exponents of the def2-SVP basis set using only energy terms computed at the same theoretical level.
• The MP-SVP basis set was tested on five benchmark sets, including halogenated molecules and dissociation energy profiles.

Main Results:

• The MP-SVP basis set demonstrated superior accuracy compared to the Complete Basis Set (CBS) extrapolation method on the tested benchmarks.
• The basis set showed good transferability and robustness across different molecular systems and interaction types.
• The MP-SVP basis set proved effective for use in composite methods like MP2.5.

Conclusions:

• The developed MP-SVP basis set significantly enhances the accuracy of MP2 calculations for noncovalent interactions.
• This new basis set offers a reliable and ab initio approach for computational studies involving weak molecular interactions.
• MP-SVP provides a valuable tool for advancing research in computational and theoretical chemistry.