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Researchers have developed a new computational framework that improves predictions of how materials respond to light and other dynamic perturbations by correcting a fundamental inconsistency in time-dependent density functional theory (TDDFT). The method adds a non-empirical correction to the exchange-correlation kernel that enforces exact physical sum rules when using advanced non-local functionals, dramatically improving agreement with experimental measurements for materials like aluminum, silicon, and carbon without increasing computational cost. The framework also demonstrates that non-local pseudopotentials have physically important effects on plasmon dispersion that are essential for accurate spectral predictions.
Why it matters
This advancement enables more accurate predictions of material properties like optical absorption, plasmon behavior, and other spectral characteristics that are crucial for designing semiconductors, photovoltaic materials, and other technologies. The method is computationally efficient and has been made freely available as open-source software, making it accessible for widespread use in materials science and chemistry research.
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⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Abstract: Advanced, orbital-dependent exchange–correlation (XC) functionals can significantly improve the description of electronic structural properties, but they substantially worsen spectral properties that are computed within standard linear-response time-dependent density functional theory frameworks. This is not a failure of the underlying Kohn-Sham states, but due to a formal inconsistency in the treatment of the dynamic density response when the non-locality of the XC potential is not taken into account consistently on the level of the full off-diagonal density matrix. To avoid these complexities, we present a non-empirical additive correction $Delta f_textnormal{xc}(mathbf{q},omega)$ to the dynamic XC kernel that re-enforces the exact f-sum rule of the non-local KS Hamiltonian within TDDFT. Comparing our new results against a representative set of accurate experimental measurements (ambient aluminum, silicon and carbon, as well as heated and compressed aluminum) reveals a dramatic improvement in all cases without any additional computational cost. The corresponding extension to the open-source GPAW code is made freely available online. We further investigate the implications of non-local pseudopotentials and show that the non-locality has an important, physically motivated effect that is indispensable to capture the correct plasmon dispersion in lieu of full all-electron simulations. In addition to being important for the estimation of a plethora of dynamic and spectral properties, our work constitutes an important step towards a universal XC functional that can be used to estimate all kinds of observables with high accuracy. Finally, we outline the potential utility of our framework for the development of advanced non-local XC functionals, and suggest a new way to rigorously verify non-local pseudopotentials against experimental measurements of collective excitations.