Toward Versatility: A Flexible Generalized Gradient Approximation Exchange Functional

Area of Science:

• Computational Chemistry
• Materials Science
• Quantum Mechanics

Background:

• Generalized Gradient Approximation (GGA) functionals are crucial for accurate electronic structure calculations.
• Existing GGA functionals like PBE and WC have limitations in describing diverse chemical and solid-state systems.
• A need exists for a versatile GGA functional applicable across various material types and bonding regimes.

Purpose of the Study:

• To develop a novel, flexible exchange (X) functional named Ghosh-Oshi-Salahub (GOS).
• To achieve unified accuracy for thermochemistry of molecules, transition metal compounds, and solids.
• To outperform established PBE and WC X functionals in predicting material properties.

Main Methods:

• Construction of the GOS functional based on a rational framework with two tunable parameters.
• Interpolation across different density variation regimes (slow, moderate, rapid).
• Rigorous satisfaction of ab initio constraints while ensuring numerical stability and analytical simplicity.

Main Results:

• The GOS functional demonstrates superior performance in predicting the thermochemistry of the G2 set molecules.
• Accurate prediction of lattice constants for periodic solids with varying conductivity.
• Outperforms PBE and WC X functionals across a broad range of chemical and solid-state applications.

Conclusions:

• GOS is a versatile and accurate GGA functional recommended for general use.
• Its performance makes it suitable for constructing hybrid functionals and pseudopotentials.
• Enables advanced molecular and solid-state applications with high accuracy.