@article{TEXTUAL,
      recid = {5355},
      author = {King, Daniel S. and Hermes, Matthew R. and Truhlar, Donald  G. and Gagliardi, Laura},
      title = {Large-Scale Benchmarking of Multireference  Vertical-Excitation Calculations via Automated Active-Space  Selection},
      journal = {Journal of Chemical Theory and Computation},
      address = {2022-09-16},
      number = {TEXTUAL},
      abstract = {We have calculated state-averaged complete-active-space  self-consistent-field (SA-CASSCF), multiconfiguration  pair-density functional theory (MC-PDFT), hybrid MC-PDFT  (HMC-PDFT), and n-electron valence state second-order  perturbation theory (NEVPT2) excitation energies with the  approximate pair coefficient (APC) automated active-space  selection scheme for the QUESTDB benchmark database of 542  vertical excitation energies. We eliminated poor active  spaces (20–40% of calculations) by applying a threshold to  the SA-CASSCF absolute error. With the remaining  calculations, we find that NEVPT2 performance is  significantly impacted by the size of the basis set the  wave functions are converged in, regardless of the quality  of their description, which is a problem absent in MC-PDFT.  Additionally, we find that HMC-PDFT is a significant  improvement over MC-PDFT with the translated PBE (tPBE)  density functional and that it performs about as well as  NEVPT2 and second-order coupled cluster on a set of 373  excitations in the QUESTDB database. We optimized the  percentage of SA-CASSCF energy to include in HMC-PDFT when  using the tPBE on-top functional, and we find the 25% value  used in tPBE0 to be optimal. This work is by far the  largest benchmarking of MC-PDFT and HMC-PDFT to date, and  the data produced in this work are useful as a validation  of HMC-PDFT and of the APC active-space selection scheme.  We have made all the wave functions produced in this work  (orbitals and CI vectors) available to the public and  encourage the community to utilize this data as a tool in  the development of further multireference model  chemistries.},
      url = {http://knowledge.uchicago.edu/record/5355},
}