Variational Density Functional Calculations of Excited States via Direct Optimization

Gianluca Levi*, Aleksei V. Ivanov, Hannes Jónsson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

The development of variational density functional theory approaches to excited electronic states is impeded by limitations of the commonly used self-consistent field (SCF) procedure. A method based on a direct optimization approach as well as the maximum overlap method is presented, and the performance is compared with previously proposed SCF strategies. Excited-state solutions correspond to saddle points of the energy as a function of the electronic degrees of freedom. The approach presented here makes use of a preconditioner determined with the help of the maximum overlap method to guide the convergence on a target nth-order saddle point. This method is found to be more robust and converge faster than previously proposed SCF approaches for a set of 89 excited states of molecules. A limited-memory formulation of the symmetric rank-one method for updating the inverse Hessian is found to give the best performance. A conical intersection for the carbon monoxide molecule is calculated without resorting to fractional occupation numbers. Calculations on the excited states of the hydrogen atom and a doubly excited state of the dihydrogen molecule using a self-interaction corrected functional are presented. For these systems, the self-interaction correction is found to improve the accuracy of density functional calculations of excited states.

Original languageEnglish
Pages (from-to)6968-6982
Number of pages15
JournalJournal of Chemical Theory and Computation
Volume16
Issue number11
DOIs
Publication statusPublished - 10 Nov 2020

Bibliographical note

Funding Information:
This work was funded by the Icelandic Research Fund (grant number 196070) and the University of Iceland Research Fund. A.V.I. is supported by a doctoral fellowship from the University of Iceland. The authors thank Elvar O?. Jo?nsson, Asmus O. Dohn, Myneni Hemanadhan, and Mats Simmermacher for useful discussions.

Funding Information:
This work was funded by the Icelandic Research Fund (grant number 196070) and the University of Iceland Research Fund. A.V.I. is supported by a doctoral fellowship from the University of Iceland. The authors thank Elvar Ö. Jónsson, Asmus O. Dohn, Myneni Hemanadhan, and Mats Simmermacher for useful discussions. a

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