Multicoefficient density functional theory (MC-DFT).

Area of Science:

• Computational Chemistry
• Quantum Chemistry

Background:

• Density Functional Theory (DFT) is a cornerstone of modern computational chemistry.
• Accurate calculation of molecular energies is essential for predicting chemical properties and reaction pathways.

Purpose of the Study:

• To systematically evaluate the performance of various pure and hybrid density functional methods.
• To investigate the impact of combining multiple basis sets on calculation accuracy.
• To determine the importance of basis set correction scaling in DFT.

Main Methods:

• Testing multiple pure and hybrid density functional approximations.
• Employing combinations of different basis sets (e.g., cc-pVDZ, cc-pVTZ, aug-cc-pVDZ).
• Calculating various molecular energy types, including atomization energies and barrier heights.

Main Results:

• Hybrid functionals generally outperform single basis set methods.
• Basis set correction scaling significantly impacts DFT accuracy.
• The B1B95 functional with a specific basis set combination achieved 1.76 kcal/mol average accuracy.

Conclusions:

• Hybrid density functionals combined with multiple basis sets offer improved accuracy for molecular energy calculations.
• Optimizing basis set usage and corrections is vital for high-fidelity DFT results.
• The B1B95 functional demonstrates state-of-the-art performance for the tested molecular properties.