Equation-of-motion orbital-optimized coupled-cluster doubles method with the density-fitting approximation: An efficient implementation.

Autor: Ünal A; Department of Chemistry, Hacettepe University, Ankara, Turkey., Bozkaya U; Department of Chemistry, Hacettepe University, Ankara, Turkey.
Jazyk: angličtina
Zdroj: Journal of computational chemistry [J Comput Chem] 2024 Dec 15; Vol. 45 (32), pp. 2969-2978. Date of Electronic Publication: 2024 Sep 05.
DOI: 10.1002/jcc.27495
Abstrakt: Orbital-optimized coupled-cluster methods are very helpful for theoretical predictions of the molecular properties of challenging chemical systems, such as excited states. In this research, an efficient implementation of the equation-of-motion orbital-optimized coupled-cluster doubles method with the density-fitting (DF) approach, denoted by DF-EOM-OCCD, is presented. The computational cost of the DF-EOM-OCCD method for excitation energies is compared with that of the conventional EOM-OCCD method. Our results demonstrate that DF-EOM-OCCD excitation energies are dramatically accelerated compared to EOM-OCCD. There are almost 17-fold reductions for the C 5 H 12 molecule in an aug-cc-pVTZ basis set with the RHF reference. This dramatic performance improvement comes from the reduced cost of integral transformation with the DF approach and the efficient evaluation of the particle-particle ladder (PPL) term, which is the most expensive term to evaluate. Further, our results show that the DF-EOM-OCCD approach is very helpful for the computation of excitation energies in open-shell molecular systems. Overall, we conclude that our new DF-EOM-OCCD implementation is very promising for the study of excited states in large-sized challenging chemical systems.
(© 2024 The Author(s). Journal of Computational Chemistry published by Wiley Periodicals LLC.)
Databáze: MEDLINE
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