Excitation energies from ground-state density-functionals by means of generator coordinates.
The generator-coordinate method is a flexible and powerful reformulation of the variational principle. Here we show that by introducing a generator coordinate in the Kohn-Sham equation of density-functional theory, excitation energies can be obtained from ground-state density functionals. As a viability test, the method is applied to ground-state energies and various types of excited-state energies of atoms and ions from the He and the Li isoelectronic series. Results are compared to a variety of alternative DFT-based approaches to excited states, in particular time-dependent density-functional theory with exact and approximate potentials.
Orestes
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Departamento de Física e Química, Instituto de Química de São Carlos, Universidade de São Paulo, Caixa Postal 780, SP 13560-970, São Carlos, Brazil.
da Silva
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Capelle
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