We investigate the performance of multiconfiguration pair-density functional theory (MC-PDFT) and complete active space second-order perturbation theory for computing the bond dissociation energies of the diatomic molecules FeC, NiC, FeS, NiS, FeSe, and NiSe, for which accurate experimental data have become recently available [Matthew, D. J.; Tieu, E.; Morse, M. D. J. Chem. Phys. 2017, 146, 144310-144320]. We use three correlated participating orbital (CPO) schemes (nominal, moderate, and extended) to define the active spaces, and we consider both the complete active space (CAS) and the separated-pair (SP) schemes to specify the configurations included for a given active space. We found that the moderate SP-PDFT scheme with the tPBE on-top density functional has the smallest mean unsigned error (MUE) of the methods considered. This level of theory provides a balanced treatment of the static and dynamic correlation energies for the studied systems. This is encouraging because the method is low in cost even for much more complicated systems.
Bibliographical noteFunding Information:
This work was supported in part by the Air Force Office of Scientific Research under Grant No. FA9550-16-1-0134 and NSF Grant CHE-1464536.
The authors are grateful to authors are grateful to Junwei Lucas Bao for helpful assistance. This work was supported in part by the Air Force Office of Scientific Research under Grant No. FA9550-16-1-0134 and NSF Grant CHE-1464536.
© 2017 American Chemical Society.