Infinite order relaxation effects for core ionization energies with a variational coupled cluster ansatz

2013 ◽  
Vol 555 ◽  
pp. 235-238 ◽  
Author(s):  
Thomas J. Watson ◽  
Rodney J. Bartlett
Keyword(s):  
Infinite Order ◽  
Coupled Cluster ◽  
Ionization Energies ◽  
Relaxation Effects

scholarly journals Dyson orbitals within the fc-CVS-EOM-CCSD framework: theory and application to X-ray photoelectron spectroscopy of ground and excited states

2020 ◽  
Vol 22 (5) ◽  
pp. 2693-2703 ◽  
Author(s):  
Marta L. Vidal ◽  
Anna I. Krylov ◽  
Sonia Coriani
Keyword(s):  
Excited States ◽  
Photoelectron Spectroscopy ◽  
Equation Of Motion ◽  
Coupled Cluster ◽  
Ionization Energies ◽  
X Ray

Ionization energies and Dyson orbitals within frozen-core core–valence separated equation-of-motion coupled cluster singles and doubles (fc-CVS-EOM-CCSD) enable efficient and reliable calculations of standard XPS and of UV-pump/XPS probe spectra.

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

2018 ◽  
Author(s):  
Marta Lopez Vidal ◽  
Xintian Feng ◽  
Evgeny Epifanovsky ◽  
Anna Krylov ◽  
Sonia Coriani
Keyword(s):  
Reference Data ◽  
Equation Of Motion ◽  
Basis Set ◽  
Target Space ◽  
Coupled Cluster ◽  
Ionization Energies ◽  
The Core ◽  
Core Approximation ◽  
Spectral Intensities ◽  
Experimental Reference

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.<br>

scholarly journals Hetero-site Double Core Ionization Energies with Sub-electronvolt Accuracy from Delta-Coupled-Cluster Calculations

2020 ◽  
Vol 124 (22) ◽  
pp. 4413-4426
Author(s):  
Xuechen Zheng ◽  
Junzi Liu ◽  
Gilles Doumy ◽  
Linda Young ◽  
Lan Cheng
Keyword(s):  
Coupled Cluster ◽  
Ionization Energies ◽  
Cluster Calculations ◽  
Coupled Cluster Calculations
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