Rethinking linearized coupled-cluster theory.
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.
Sandia National Laboratories, Albuquerque, New Mexico 87185, USA. agtaube@sandia.gov
Andrew G
AG
Taube
Rodney J
RJ
Bartlett