Canonical versus explicitly correlated coupled cluster: Post‐complete‐basis‐set extrapolation and the quest of the complete‐basis‐set limit

2020 ◽  
Author(s):  
António J. C. Varandas
Keyword(s):  
Basis Set ◽  
Coupled Cluster ◽  
Complete Basis ◽  
Complete Basis Set ◽  
Explicitly Correlated ◽  
Complete Basis Set Limit ◽  
Basis Set Extrapolation

Post-complete-basis-set extrapolation of conventional and explicitly correlated coupled-cluster energies: can the convergence to the CBS limit be diagnosed?

2021 ◽  
Vol 23 (14) ◽  
pp. 8717-8730 ◽  
Author(s):  
A. J. C. Varandas
Keyword(s):  
Basis Set ◽  
Coupled Cluster ◽  
Complete Basis ◽  
Complete Basis Set ◽  
Explicitly Correlated ◽  
Test Sets ◽  
Basis Set Extrapolation

We assess benchmark correlation energies for 130 systems in test sets A24 and TS-106 both with the canonical CCSD(T) and explicitly correlated CCSD(T)-F12 methods.

Group IIIa Hydrides XH2 and XH2- (X = B, Al, Ga): Electron Affinities and Singlet-Triplet Splittings Revisited

2003 ◽  
Vol 68 (1) ◽  
pp. 75-88 ◽  
Author(s):  
Ivan Černušák ◽  
Alena Zavažanová ◽  
Juraj Raab ◽  
Pavel Neogrády
Keyword(s):  
Ground State ◽  
Basis Set ◽  
Basis Sets ◽  
Coupled Cluster ◽  
Electron Affinities ◽  
Complete Basis ◽  
Complete Basis Set ◽  
Order Of Magnitude ◽  
Complete Basis Set Limit ◽  
Cluster Methods

Geometries, electron affinities (EA) and singlet-triplet (S-T) splittings of XH2/XH2- molecules (X = B, Al, Ga) are calculated by coupled-cluster methods, using the sequence of basis sets. The EA values and S-T splittings for aluminium and gallium dihydrides are an order of magnitude larger (in absolute values) than those for boron. For boron and aluminium dihydrides, two types of extrapolations towards complete basis set limit are applied, leading to EA = 0.24 eV, ST = -0.01 eV (BH2), and EA = 1.10 eV, ST = -0.62 eV. The best calculated values for gallium dihydrides are EA = 1.13 eV and ST = -0.74 eV. All three S-T splittings favour singlet as the ground state, although the S-T splittings of BH2- is exceptionally small. In addition, vertical electron affinities and vertical electron detachments are reported for these molecules.

From CCSD(T)/aug-cc-pVTZ-J to CCSD(T) complete basis set limit isotropic nuclear magnetic shieldings via affordable DFT/CBS calculations

2011 ◽  
Vol 49 (5) ◽  
pp. 231-236 ◽  
Author(s):  
Teobald Kupka ◽  
Michał Stachów ◽  
Marzena Nieradka ◽  
Jakub Kaminsky ◽  
Tadeusz Pluta ◽  
...  
Keyword(s):  
Basis Set ◽  
Complete Basis ◽  
Complete Basis Set ◽  
Complete Basis Set Limit ◽  
Nuclear Magnetic
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