Extended screened exchange functional derived from transcorrelated density functional theory.

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Materials Science

Background:

• Density functional theory (DFT) is a powerful quantum mechanical modeling method.
• Accurate correlation energy functionals are crucial for reliable DFT predictions.
• Existing functionals often suffer from self-interaction errors and computational cost.

Purpose of the Study:

• To develop a novel correlation energy functional based on the transcorrelated method.
• To create a functional that is free from self-interaction errors.
• To assess the computational efficiency and accuracy of the new functional.

Main Methods:

• Formulation of an effective Hamiltonian (H_TC) via similarity transformation.
• Derivation of the extended screened exchange (ESX) functional from the TC-DFT framework.
• Parametrization of the ESX functional using the homogeneous electron gas correlation energy.

Main Results:

• The ESX functional is derived within two-body integrals and is self-interaction-free.
• Computational cost is comparable to the Hartree-Fock method.
• Successful application to electronic structure calculations for silicon, H- ion, and atoms.

Conclusions:

• The TC-DFT formulation provides a promising route for systematic improvement of correlation functionals.
• The ESX functional demonstrates potential for accurate and efficient electronic structure calculations.
• This approach offers a viable alternative to existing correlation functionals in DFT.