2017/07/31 by M. Chandler Bennett, Cody A. Melton, Abdulgani Annaberdiyev +3 · 1 citation
Physics and Astronomy · #physics.chem-ph #cond-mat.mtrl-sci #physics.atom-ph #physics.comp-ph
paper · pdf · doi:10.1063/1.4995643
14 pages, 14 figures, 11 tables
arxiv created 2017/11/28 · arxiv updated 2017/11/29
We outline ideas on desired properties for a new generation of effective core potentials (ECPs) that will allow valence-only calculations to reach the full potential offered by recent advances in many-body wave function methods. The key improvements include consistent use of correlated methods throughout ECP constructions and improved transferability as required for an accurate description of molecular systems over a range of geometries. The guiding principle is the isospectrality of all-electron and ECP Hamiltonians for a subset of valence states. We illustrate these concepts on a few first- and second-row atoms (B, C, N, O, S) and we obtain higher accuracy in transferability than previous constructions while using a semi-local ECPs with a small number of parameters. In addition, the constructed ECPs enable many-body calculations of valence properties with higher (or same) accuracy than their all-electron counterparts with uncorrelated cores. This implies that the ECPs include also some of the impacts of core-core and core-valence correlations on valence properties. The results open further prospects for ECP improvements and refinements.