2016/03/02 by Kevin P. Hannon, Chenyang Li, Francesco A. Evangelista · 52 citations
Chemistry · Mathematics · Physics and Astronomy · #Advanced Chemical Physics Studies #Advanced NMR Techniques and Applications #Basis set #Chemistry #Computational chemistry #Coupled cluster #Density functional theory #Mathematical physics #Mathematics #Molecule #Perturbation theory (quantum mechanics) #Physics #Quantum mechanics #Renormalization group #Singlet state #Spectroscopy and Quantum Chemical Studies #physics.chem-ph
paper · pdf · doi:10.1063/1.4951684
published in The Journal of Chemical Physics 144(20), 204111 (American Institute of Physics)
arxiv created 2016/03/02 · openalex publication_date 2016/05/26 · arxiv updated 2016/06/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We report an efficient implementation of a second-order multireference perturbation theory based on the driven similarity renormalization group (DSRG-MRPT2) [C. Li and F. A. Evangelista, J. Chem. Theory Comput. 11, 2097 (2015)]. Our implementation employs factorized two-electron integrals to avoid storage of large four-index intermediates. It also exploits the block structure of the reference density matrices to reduce the computational cost to that of second-order Møller-Plesset perturbation theory. Our new DSRG-MRPT2 implementation is benchmarked on ten naphthyne isomers using basis sets up to quintuple-ζ quality. We find that the singlet-triplet splittings (ΔST) of the naphthyne isomers strongly depend on the equilibrium structures. For a consistent set of geometries, the ΔST values predicted by the DSRG-MRPT2 are in good agreements with those computed by the reduced multireference coupled cluster theory with singles, doubles, and perturbative triples.