Excited states from range-separated density-functional perturbation theory

Rebolini, Elisa; Toulouse, Julien; Teale, Andrew M.; Helgaker, Trygve; Savin, Andreas

Abstract

We explore the possibility of calculating electronic excited states by using perturbation theory along a range-separated adiabatic connection. Starting from the energies of a partially interacting Hamiltonian, a first-order correction is defined with two variants of perturbation theory: a straightforward perturbation theory, and an extension of the Görling-Levy one that has the advantage of keeping the ground-state density constant at each order in the perturbation. Only the first, simpler, variant is tested here on the helium and beryllium atoms and on the hydrogen molecule. The first-order correction within this perturbation theory improves significantly the total ground- and excited-state energies of the different systems. However, the excitation energies mostly deteriorate with respect to the zeroth-order ones, which may be explained by the fact that the ionization energy is no longer correct for all interaction strengths. The second (Görling-Levy) variant of the perturbation theory should improve these results but has not been tested yet along the range-separated adiabatic connection.

Citation

Rebolini, E., Toulouse, J., Teale, A. M., Helgaker, T., & Savin, A. (2015). Excited states from range-separated density-functional perturbation theory. Molecular Physics, 113(13-14), 1740-1749. https://doi.org/10.1080/00268976.2015.1011248

• Journal Article Type: Article
• Acceptance Date: Jan 19, 2015
• Online Publication Date: Feb 18, 2015
• Publication Date: Jul 18, 2015
• Deposit Date: Dec 16, 2015
• Publicly Available Date: Dec 16, 2015
• Journal: Molecular Physics
• Print ISSN: 0026-8976
• Electronic ISSN: 1362-3028
• Publisher: Taylor & Francis Open
• Peer Reviewed: Peer Reviewed
• Volume: 113
• Issue: 13-14
• Pages: 1740-1749
• DOI: https://doi.org/10.1080/00268976.2015.1011248
• Public URL: https://nottingham-repository.worktribe.com/output/744883
• Publisher URL: http://www.tandfonline.com/doi/full/10.1080/00268976.2015.1011248
• Additional Information: Peer Review Statement: The publishing and review policy for this title is described in its Aims & Scope.; Aim & Scope: http://www.tandfonline.com/action/journalInformation?show=aimsScope&journalCode=tmph20