Size-consistent explicitly correlated triple excitation correction

A new approach is proposed to reduce the basis set incompleteness error of the triple excitation correction in explicitly correlated coupled-cluster singles and doubles with perturbative triples calculations. Our method is similar to the intuitive triples correction approach of Knizia et al. [J. Che...

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Bibliographic Details
Published in:The Journal of chemical physics 2021-07, Vol.155 (3), p.034107-034107
Main Authors: Kállay, Mihály, Horváth, Réka A., Gyevi-Nagy, László, Nagy, Péter R.
Format: Article
Language:English
Subjects:
Atomizing
Error correction
Excitation
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Summary:A new approach is proposed to reduce the basis set incompleteness error of the triple excitation correction in explicitly correlated coupled-cluster singles and doubles with perturbative triples calculations. Our method is similar to the intuitive triples correction approach of Knizia et al. [J. Chem. Phys. 130, 054104 (2009)] but, in contrast to the latter, is size-consistent. The new approximation is easy to implement, and its overhead is negligible with respect to the conventional (T) correction. The performance of the approach is assessed for atomization, reaction, and interaction energies as well as for bond lengths and harmonic vibrational frequencies. The advantages of its size consistency are also demonstrated.
ISSN:0021-9606
1089-7690
DOI:10.1063/5.0057426