A local hybrid exchange functional approximation from first principles.

Area of Science:

• Quantum Chemistry
• Computational Materials Science

Background:

• Local hybrid functionals offer flexibility via position-dependent exact exchange.
• Previous functionals relied on benchmark data, complicating design.
• A need exists for ab initio designed functionals adhering to theoretical constraints.

Purpose of the Study:

• To develop a local hybrid functional using an ab initio approach.
• To construct a functional without reliance on empirical benchmark data.
• To assess the performance of the new functional across diverse chemical properties.

Main Methods:

• Utilized principles of modern meta-generalized gradient approximations.
• Employed density matrix expansion and a local mixing function.
• Incorporated an approximate correlation length for functional design.

Main Results:

• The new functional shows robust performance for atomization energies, barrier heights, and excitation energies.
• Accurate predictions were achieved for nuclear magnetic resonance (NMR) spin-spin coupling constants and electron paramagnetic resonance (EPR) properties.
• Performance for NMR chemical shifts was less accurate compared to other properties.

Conclusions:

• The developed functional represents a significant step towards ab initio design of local hybrid functionals.
• The ab initio construction method offers a more theoretically grounded approach.
• The functional is well-suited for applications requiring accurate predictions of electronic and magnetic properties.