Assessment of a Middle-Range Hybrid Functional

Area of Science:

• Computational chemistry
• Quantum mechanics
• Materials science

Background:

• Modern Kohn-Sham density functional theory relies on hybrid functionals.
• Hybrid functionals face challenges in solid-state calculations due to the slow decay of exact exchange, leading to high computational costs and unphysical effects.
• Screened hybrids using short-range exact exchange can mitigate these issues, but some molecular properties benefit from long-range exact exchange.

Purpose of the Study:

• To benchmark the performance of the HISS functional, which utilizes middle-range exact exchange.
• To investigate the importance of middle-range exact exchange for systems sensitive to asymptotic exchange potentials.
• To apply the HISS functional to the dissociation of homonuclear diatomic cations and the polarizability of linear H2 chains.

Main Methods:

• Development and application of the HISS (Hybridization with Intermediate-range Screening) functional.
• Benchmarking against established methods for simple properties.
• Computational studies on homonuclear diatomic cation dissociation and H2 chain polarizability.

Main Results:

• The HISS functional offers a reconciliation of short-range and long-range exact exchange requirements.
• Performance was evaluated for systems sensitive to the asymptotic exchange potential.
• The study provides insights into the role of middle-range exact exchange in specific chemical systems.

Conclusions:

• The HISS functional presents a novel approach to hybrid functionals in density functional theory.
• Middle-range exact exchange is crucial for accurately describing certain properties, particularly those involving asymptotic behavior.
• This work expands the utility of density functional theory for complex systems.