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Simultaneous determination of structures, vibrations, and frontier orbital energies from a self-consistent range-separated hybrid functional
I. Tamblyn, S. Refaely-Abramson, J.B. Neaton, and L. Kronik Journal of Physical Chemistry Letters, 5, 2734 (2014) Achieving accurate predictions of molecular geometries, vibrational properties, and ionization energies simultaneously using a single theoretical approach has been a longstanding challenge in computational chemistry. In this work, we develop a self-consistent optimally tuned range-separated hybrid (scOT-RSH) density functional theory approach that addresses this challenge. The key innovation involves systematically optimizing the range-separation parameter to satisfy the ionization energy theorem while simultaneously minimizing interatomic forces. Benchmarking against the G2 test set, the scOT-RSH approach achieves a mean absolute error of only 0.2 eV relative to experimental ionization energies, compared to 2.96 eV with the widely used B3LYP functional, while molecular geometries remain comparable to B3LYP results. This methodology establishes a new paradigm in which accurate geometries and ionization energies can be predicted simultaneously from a single functional approach with enhanced reliability. |
