Reaching for the performance limit of hybrid density functional theory for molecular chemistry

Jiashu Liang; Martin Head-Gordon

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arXiv · 2603.23466

Reaching for the performance limit of hybrid density functional theory for molecular chemistry

Jiashu Liang·Martin Head-Gordon

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Abstract

Density functional theory (DFT) offers an exceptional balance between accuracy and efficiency, but practical density functional approximations face an unavoidable trade-off among simplicity, accuracy, and transferability. A systematic protocol is therefore needed to develop functionals that are reliably most accurate within a chosen application domain. Here we present such a protocol by combining constraint enforcement, flexible functional forms, and modern optimization. Applying this strategy to the range-separated hybrid (RSH) meta-GGA framework, we obtain the carefully optimized and appropriately constrained hybrid (COACH) functional. Across broad molecular benchmarks, COACH improves both accuracy and transferability relative to leading RSH meta-GGAs, including \omegaB97M-V, while retaining the computational practicality of its rung. Finally, our analysis of the remaining trade-offs and saturation behavior suggests that further systematic progress will likely require the incorporation of genuinely nonlocal information.

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Jiashu Liang, Martin Head-Gordon. 2026-03-24. Reaching for the performance limit of hybrid density functional theory for molecular chemistry. https://arxiv.org/abs/2603.23466

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