Range-separated multideterminant density-functional theory with a short-range correlation functional of the on-top...

Area of Science:

• Quantum Chemistry
• Computational Physics
• Materials Science

Background:

• Density-functional theory (DFT) is a powerful tool for electronic structure calculations.
• Accurately describing electron correlation, especially static correlation, remains a challenge in DFT.
• Range-separated DFT offers a way to improve correlation energy approximations.

Purpose of the Study:

• To introduce a novel approximation for the short-range correlation energy functional.
• To develop a method applicable to multideterminantal references within range-separated DFT.
• To accurately capture static correlation effects.

Main Methods:

• Developed a local functional dependent on density, density gradient, and on-top pair density.
• The functional interpolates between Perdew-Burke-Ernzerhof and exact asymptotic expansions.
• Combined with selected configuration interaction for long-range wave functions.

Main Results:

• Achieved accurate dissociation energy curves for H2, Li2, and Be2 molecules.
• The approximation effectively accounts for static correlation.
• Demonstrated the utility of the local functional in range-separated DFT.

Conclusions:

• The proposed approximation is a promising method for static correlation in range-separated DFT.
• This approach can lead to more accurate predictions of molecular properties.
• Further applications in computational chemistry and materials science are anticipated.