Lancaster EPrints

Molecular excited states from the SCAN functional

Tozer, David J. and Peach, Michael Joseph George (2018) Molecular excited states from the SCAN functional. Molecular Physics, 116 (11). pp. 1504-1511. ISSN 0026-8976

[img]
Preview
PDF (paper_forsubmission) - Draft Version
Download (244Kb) | Preview
    [img] PDF (paper_forsubmission) - Submitted Version
    Restricted to Repository staff only until 08 April 2019.
    Available under License Creative Commons Attribution-NonCommercial.

    Download (245Kb)

      Abstract

      The performance of the strongly constrained and appropriately normed (SCAN) [Phys. Rev. Lett. 115, 036402 (2015)] meta-generalised gradient approximation exchange–correlation functional is investigated for the calculation of time-dependent density-functional theory (TDDFT) molecular excitation energies of local, charge-transfer, and Rydberg character, together with the excited 3Σ+u potential energy curve in H2. The SCAN results frequently resemble those obtained using a global hybrid functional, with either a standard or increased fraction of exact orbital exchange. For local excitations, SCAN can exhibit significant triplet instability problems, resulting in imaginary triplet excitation energies for a number of cases. The Tamm–Dancoff approximation offers a simple approach to improve the situation, but the excitation energies are still significantly underestimated. Understanding the origin of these (near)-triplet instabilities may provide useful insight into future functional development.

      Item Type: Journal Article
      Journal or Publication Title: Molecular Physics
      Additional Information: This is an Accepted Manuscript of an article published by Taylor & Francis in Molecular Physics on 08/04/2018, available online: http://www.tandfonline.com/10.1080/00268976.2018.1453094
      Uncontrolled Keywords: Density-functional theory ; exchange–correlation functionals ; time-dependent DFT ; excited states ; triplet instabilities
      Subjects:
      Departments:
      ID Code: 124473
      Deposited By: ep_importer_pure
      Deposited On: 12 Apr 2018 16:10
      Refereed?: Yes
      Published?: Published
      Last Modified: 13 Nov 2018 00:47
      Identification Number:
      URI: http://eprints.lancs.ac.uk/id/eprint/124473

      Actions (login required)

      View Item