ChemRxiv
These are preliminary reports that have not been peer-reviewed. They should not be regarded as conclusive, guide clinical practice/health-related behavior, or be reported in news media as established information. For more information, please see our FAQs.
1/1
2 files

A New and Efficient Equation-of-Motion Coupled-Cluster Framework for Core-Excited and Core-Ionized States

preprint
revised on 15.02.2019, 12:22 and posted on 15.02.2019, 20:34 by Marta L. Vidal, Xintian Feng, Evgeny Epifanovsky, Anna Krylov, Sonia Coriani
We present a fully analytical implementation of the core-valence separation (CVS) scheme for the equation-of-motion (EOM) coupled-cluster singles and doubles (CCSD) method for calculations of core-level states. In the spirit of the original CVS approximation proposed by Cederbaum, Domcke and Schirmer, pure valence excitations are excluded from the EOM target space and the frozen-core approximation is imposed on the reference-state amplitudes and multipliers. This yields an efficient, robust, and accurate EOM-CCSD framework for calculations of excitation and ionization energies as well as state and transition properties (e.g., spectral intensities, natural transition and Dyson orbitals). The accuracy of the new scheme is improved relative to the results obtained applying the CVS only during the solution of the EOM eigenvalue equations. The errors in absolute excitation/ionization energies relative to the experimental reference data are of the order of 0.2{3.0 eV, depending on the K-edge considered and on the basis set used, and the shifts are systematic for each edge.

History

Email Address of Submitting Author

malop@kemi.dtu.dk

Institution

Technical University of Denmark

Country

Denmark

ORCID For Submitting Author

0000-0003-0653-2078

Declaration of Conflict of Interest

No conflict of interest

Exports