Consistent structures and interactions by density functional theory with small atomic orbital basis sets.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Materials Science

Background:

• Accurate electronic structure calculations are crucial for understanding chemical systems.
• Existing methods often face challenges with large systems, computational cost, or specific interaction types.
• There is a need for efficient and accurate computational tools in theoretical chemistry and physics.

Purpose of the Study:

• To develop a novel composite electronic structure approach for efficient computation of large chemical systems.
• To create a low-cost method that accurately describes structural parameters and interaction energies.
• To provide a robust computational tool for routine application in theoretical chemistry and physics.

Main Methods:

• Density Functional Theory (DFT) based composite electronic structure approach.
• Utilizing the Perdew-Burke-Ernzerhoff (PBE) generalized-gradient-approximation in a modified global hybrid functional.
• Employing Ahlrichs-type valence-double zeta atomic orbital (AO) Gaussian basis sets and atom-pairwise potentials for BSSE correction and dispersion effects.

Main Results:

• PBEh-3c demonstrates good performance for thermochemical properties and excellent accuracy for non-covalent interaction energies.
• The method achieves deviations from reference data comparable to MP2/TZ but at a fraction of the computational cost.
• Periodic calculations for molecular crystals show high accuracy for structures and sublimation enthalpies, competitive with plane-wave methods.

Conclusions:

• PBEh-3c is a low-cost, BSSE-free, and physically sound electronic structure method.
• It offers high accuracy for structural parameters and interaction energies in various chemical systems, including large and periodic ones.
• The method is suitable for routine application to systems with hundreds of atoms, serving as a high-speed computational tool.