Third-order unitary coupled cluster (UCC3) for excited electronic states

• Verfasst von: Hodecker, Manuel [VerfasserIn]
• Verfasst von: Thielen, Sebastian M. [VerfasserIn]
• Verfasst von: Rehn, Dirk R. [VerfasserIn]
• Verfasst von: Dreuw, Andreas [VerfasserIn]
• Titel: Third-order unitary coupled cluster (UCC3) for excited electronic states
• Titelzusatz: efficient implementation and benchmarking
• Verf.angabe: Manuel Hodecker, Sebastian M. Thielen, Junzi Liu, Dirk R. Rehn, and Andreas Dreuw
• E-Jahr: 2020
• Jahr: 12 May 2020
• Umfang: 10 S.
• Teil: volume:16
• Teil: year:2020
• Teil: number:6
• Teil: pages:3654-3663
• Teil: extent:10
• Fussnoten: Gesehen am 23.07.2020
• Titel Quelle: Enthalten in: Journal of chemical theory and computation
• Ort Quelle: Washington, DC, 2004
• Jahr Quelle: 2020
• Band/Heft Quelle: 16(2020), 6, Seite 3654-3663
• ISSN Quelle: 1549-9626
• DOI: doi:10.1021/acs.jctc.0c00335
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1725376083

Abstract

The efficient implementation of the third-order unitary coupled-cluster scheme (UCC3) for the calculation of excited electronic states is reported. The UCC3 scheme and its second-order UCC2 variant have been benchmarked and compared to Jacquemin’s recently introduced, as well as Thiel’s well-established, benchmark sets for excitation energies and oscillator strengths. For the latter, the calculation of 134 excited singlet and 71 excited triplet states of 28 small- to medium-sized organic molecules has revealed that UCC2 exhibits a mean error and standard deviation of 0.36 ± 0.41 eV for singlet states and 0.22 ± 0.21 eV for triplet states, whereas UCC3 revealed an accuracy of 0.06 ± 0.27 eV for singlet and −0.22 ± 0.15 eV for triplet states. In addition, the oscillator strengths obtained with effective transition moments correct through second order in perturbation theory are in very good agreement with literature data.