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arXiv · 1707.03939

A New Generation of Effective Core Potentials for Correlated Calculations

M. Chandler Bennett·Cody A. Melton·Abdulgani Annaberdiyev·Guangming Wang·Luke Shulenburger·Lubos Mitas
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Abstract

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.

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M. Chandler Bennett, Cody A. Melton, Abdulgani Annaberdiyev, Guangming Wang, Luke Shulenburger, Lubos Mitas. 2017-07-13. A New Generation of Effective Core Potentials for Correlated Calculations. https://doi.org/10.1063/1.4995643

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