Small-Basis Set Density-Functional Theory Methods Corrected with Atom-Centered Potentials.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Theoretical Chemistry

Background:

• Density Functional Theory (DFT) is widely used for modeling noncovalent interactions and thermochemistry.
• Inaccurate DFT functionals and limited basis sets are primary error sources for chemical property predictions.
• Accurate calculations necessitate appropriate functionals and large basis sets, increasing computational cost.

Purpose of the Study:

• To introduce three new DFT methods incorporating atom-centered potentials (ACPs) for improved accuracy.
• To develop ACPs for elements H, B, C, N, O, F, Si, P, S, and Cl.
• To minimize errors in predicted chemical properties while maintaining low computational expense.

Main Methods:

• Developed three ACP-corrected DFT methods: BLYP/6-31G*-ACP, M06-2X/6-31G*-ACP, and CAM-B3LYP/6-31G*-ACP.
• ACPs are one-electron potentials designed to correct DFT/basis-set deficiencies.
• Optimized ACP parameters using an extensive dataset (118,655 points) of high-quality computational data.

Main Results:

• ACP-corrected methods demonstrated accuracy comparable to high-level wavefunction theory methods.
• Achieved accuracy close to complete basis set (CBS) limit calculations.
• Maintained computational cost similar to double-ζ DFT methods.

Conclusions:

• The new BLYP/6-31G*-ACP, M06-2X/6-31G*-ACP, and CAM-B3LYP/6-31G*-ACP methods offer a balance of accuracy and efficiency.
• These ACP-corrected DFT methods are well-suited for large molecular systems.
• Enables accurate prediction of noncovalent, thermochemical, and kinetic properties with reduced computational resources.