Non-iterative doubles corrections to the random phase and higher random phase approximations: singlet and triplet excitation energies

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Pi Ariane Bresling Haase, Rasmus Faber, Patricio F. Provasi, Stephan P. A. Sauer

The second-order non-iterative doubles corrected RPA method (RPA(D)) has been extended to triplet excitation energies and the doubles corrected HRPA method (HRPA(D)) as well as a shifted version (s-HRPA(D)) for calculating singlet and triplet excitation energies are presented here for the first time. A benchmark set consisting of 20 molecules with a total of 117 singlet and 71 triplet excited states has been used to test the performance of the new methods by comparison with previous results obtained with the SOPPA and the CC3 methods. In general, the second-order doubles corrections to RPA and HRPA significantly reduce both the mean deviation as well as the standard deviation of the errors compared to the CC3 results. The new methods approach the accuracy of the SOPPA method while using only 10 - 60% of the calculation time.
Original languageEnglish
JournalJournal of Computational Chemistry
Volume41
Issue number1
Pages (from-to)43-55
ISSN0192-8651
DOIs
Publication statusPublished - 5 Jan 2020

    Research areas

  • The Faculty of Science - RPA(D), HRPA(D), Excitation Energy, SOPPA, Quantum Chemistry, Computational Chemistry

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