Non-Covalent Molecular Interaction Rules to Define Internal Dimer Coordinates for Quantum Mechanical Potential Energy...

Area of Science:

• Computational Chemistry
• Molecular Modeling
• Quantum Mechanics

Background:

• Non-covalent interactions (NCI) are crucial for condensed phase systems.
• Quantum mechanical (QM) methods accurately estimate interaction energies and geometries.
• Current methods for determining monomer orientation in dimers are often limited, hindering detailed analysis of specific atomic contributions.

Purpose of the Study:

• To develop a systematic workflow for controlling monomer interaction orientation in dimers.
• To enable automated generation and analysis of potential energy scans (PES) for a wide range of molecular dimers.
• To improve the understanding of specific contributions of different functional groups to intermolecular interactions.

Main Methods:

• Introduction of a "MIR workflow" utilizing molecular interaction rules (MIR) and Z-matrices for controlled orientation.
• Automated generation of 10,616 interaction dimers from 89 monomers.
• Calculation of PES using QM methods (HF/6-31G*, MP2/6-31G*, ωb97x-d3/6-31G*, aug-cc-pVDZ) and storage in an extendable database.

Main Results:

• Demonstration of the workflow's utility across diverse functional groups and interaction types.
• Analysis of specific dimer interactions (benzene, azetidinone-acetamide, pyridine-acetone) under controlled orientations.
• Quantification of the impact of different QM model chemistries on interaction energies and distances, highlighting dispersion contributions.

Conclusions:

• The MIR workflow provides a robust method for systematic investigation of NCI by controlling monomer orientation.
• This approach facilitates a deeper understanding of intermolecular forces and aids in the optimization of computational models.
• The study emphasizes the importance of dispersion forces and the influence of QM methods on interaction energy calculations.