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Updated: Feb 6, 2026

Paraffin-Embedded and Frozen Sections of Drosophila Adult Muscles
Published on: December 27, 2010
Excitation energies of embedded open-shell systems: Unrestricted frozen-density-embedding time-dependent
Michael Böckers1, Johannes Neugebauer1
1Theoretische Organische Chemie, Organisch-Chemisches Institut and Center for Multiscale Theory and Computation, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany.
Abstract:
Frozen-density-embedding (FDE) linear response time-dependent density functional theory (TDDFT) is generalized to the case of spin-unrestricted reference orbitals. FDE-TDDFT in the uncoupled approximation is applied to calculate vertical excitation energies of diatomic radicals interacting with closed-shell atoms (helium) or molecules like water. Unrestricted FDE-TDDFT can reproduce the vertical valence excitation energies obtained from conventional supermolecular TDDFT with good accuracy, provided that a good embedding potential is available. To investigate the influence of approximate embedding potentials, we also combine the unrestricted FDE-TDDFT formalism with projection-operator and potential reconstruction techniques, thus enabling calculations with accurate ("exact") embedding potentials.
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