Completely renormalized coupled clusters

The isomerization process interconverting the three isomers depicted in Figure 4, with and without ammonia ligands, has been studied recently,54 58 using the completely renormalized coupled cluster level of theory, including... [Pg.265]

Keywords Coupled-cluster theory Local correlation methods Cluster-inmolecule formalism Linear scaling algorithms Single-reference coupled-cluster methods CCSD approach CCSD(T) approach Completely renormalized coupled-cluster approaches CR-CC(2,3) approach Large molecular systems Bond breaking Normal alkanes Water clusters... [Pg.131]

New noniterative coupled-cluster methods for bond breaking the method of moments of coupled-cluster equations and its quadratic variant and the renormalized and completely renormalized coupled-cluster approaches... [Pg.126]

We have overviewed the new approach to the many-electron correlation problem in atoms and molecules, termed the method of moments of coupled-cluster equations (MMCC). The main idea of the MMCC theory is that of the noniterative energy corrections which, when added to the ground- and excited-state energies obtained in approximate CC calculations, recover the exeict energies. We have demonstrated that the MMCC formalism leads to a number of useful approximations, including the renormalized and completely renormalized CCSD(T), CCSD(TQ), and CCSDT(Q) methods for... [Pg.59]

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