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Updated: Jun 24, 2026

Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry
Published on: April 8, 2020
Rethinking linearized coupled-cluster theory
Andrew G Taube1, Rodney J Bartlett
1Sandia National Laboratories, Albuquerque, New Mexico 87185, USA. agtaube@sandia.gov
Abstract:
Hermitian linearized coupled-cluster methods have several advantages over more conventional coupled-cluster methods including facile analytical gradients for searching a potential energy surface. A persistent failure of linearized methods, however, is the presence of singularities on the potential energy surface. A simple Tikhonov regularization procedure is introduced that can eliminate this singularity. Application of the regularized linearized coupled-cluster singles and doubles (CCSD) method to both equilibrium structures and transition states shows that it is competitive with or better than conventional CCSD, and is more amenable to parallelization.
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