A Mountaineering Strategy to Excited States: Highly Accurate Energies and Benchmarks for Medium Sized Molecules

• DOI: 10.1021/acs.jctc.9b01216
• Publication Date: 2020-01-27T21:41:36Z
• Authors: Pierre-François Loos; Filippo Lipparini; Martial Boggio-Pa...; Anthony Scemama; Denis Jacquemin
• Keywords: Coupled cluster

Following our previous work focussing on compounds containing up to 3 non-hydrogen atoms [\emph{J. Chem. Theory Comput.} {\bfseries 14} (2018) 4360--4379], we present here highly-accurate vertical transition energies obtained for 27 molecules encompassing 4, 5, and 6 atoms. To obtain these energies, use equation-of-motion coupled cluster theory the highest technically possible excitation order systems (CC3, EOM-CCSDT, EOM-CCSDTQ), selected configuration interaction (SCI) calculations (with tens of millions determinants in reference space), as well multiconfigurational $n$-electron valence state perturbation (NEVPT2) method. All approaches are applied combination with diffuse-containing atomic basis sets. For all transitions, report at least CC3/\emph{aug}-cc-pVQZ CC3/\emph{aug}-cc-pVTZ oscillator strengths each dipole-allowed transition. We show that CC3 almost systematically delivers agreement higher-level methods a typical deviation $\pm 0.04$ eV, except transitions dominant double character where error is much larger. The contribution gathers large, diverse accurate set more than 200 states various natures (valence, Rydberg, singlet, triplet, $n \rightarrow \pi^*$, $\pi \ldots). this series theoretical best estimates benchmark popular excited calculations: CIS(D), ADC(2), CC2, STEOM-CCSD, EOM-CCSD, CCSDR(3), CCSDT-3, CC3, NEVPT2. results benchmarks compared available literature data.