Semiclassical Dispersion Corrections Efficiently Improve Multiconfigurational Theory with Short-Range...

Area of Science:

• Quantum Chemistry
• Computational Chemistry
• Theoretical Chemistry

Background:

• Multiconfigurational wave functions qualitatively describe electronic structure but struggle with quantitative reaction energies.
• Dynamic correlation, crucial for accuracy, requires considering many configurations beyond the active space.
• Standard methods like multireference perturbation theory face accuracy limitations and high computational costs.

Purpose of the Study:

• To develop a hybrid approach for accurate calculation of reaction energies and electronic structures.
• To incorporate dynamic correlation efficiently without double counting.
• To reduce the computational cost associated with high-accuracy quantum chemical methods.

Main Methods:

• Proposed a multiconfigurational (MC) wave function theory combined with short-range (sr) density functional theory (DFT) and semiclassical dispersion (D) corrections.
• MC-srDFT-D approach covers long-range dynamic correlation via dispersion corrections and short-range dynamic correlation via DFT.
• Ensured no double counting of correlation effects between MC-WFT and DFT.

Main Results:

• The MC-srDFT-D hybrid approach demonstrates very good reliability for quantitative reaction energies.
• This method effectively captures both short-range and long-range dynamic correlation.
• Achieved high accuracy at a negligible computational cost compared to standard methods.

Conclusions:

• The MC-srDFT-D approach offers a computationally efficient and reliable method for electronic structure calculations.
• It overcomes the limitations of standard multireference perturbation theory, particularly in handling dispersion interactions.
• This hybrid method provides a promising direction for accurate quantum chemical predictions.