Reliable Dimerization Energies for Modeling of Supramolecular Junctions

Area of Science:

• Computational chemistry
• Materials science
• Quantum chemistry

Background:

• Accurate estimation of intermolecular interaction energy (ΔE) is essential for modeling organic electronic materials.
• Benchmark data for ΔE are needed to evaluate computational methods.

Purpose of the Study:

• To compile benchmark ΔE data for a diverse set of 50 dimers (Set50-50).
• To assess the performance of various density-functional theory (DFT) and localized coupled cluster methods against benchmark data.
• To identify cost-effective and reliable methods for calculating ΔE.

Main Methods:

• Focal-point strategy using coupled cluster theory with singles, doubles, and perturbative triples [CCSD(T)] with large basis sets.
• Extrapolation of energy components to the complete basis set (CBS) limit.
• Evaluation of DFT-based approaches and a localized CCSD(T) method on the Set50-50 dataset.

Main Results:

• A proposed "silver standard" approach (localized CCSD(T) with CBS extrapolations) achieves accuracy better than 2 kJ/mol for absolute ΔE values.
• The computationally inexpensive "ωB97X-3c/vDZP" DFT method demonstrated remarkable performance.
• Established benchmark data for 50 diverse dimers, including models of single-stacking junctions.

Conclusions:

• The "silver standard" method provides highly accurate ΔE values for noncovalent complexes.
• The ωB97X-3c/vDZP method offers a computationally efficient and reliable alternative for ΔE calculations.
• Findings facilitate cost-effective searches of potential energy surfaces for noncovalent interactions.