The recent advent of the density matrix renormalization group (DMRG) theory has delivered
a new capability to compute multireference (MR) wave function with large configuration …

Canonical transformation (CT) theory targets the description of dynamic correlation in
multireference quantum chemistry problems. When combined with a static correlation …

New coupled-cluster methods (UCC (n)) for correlation energies and properties are
developed based upon a unitary cluster ansatz and a finite-order truncation of the energy …

We propose a theory to describe dynamic correlations in bonding situations where there is
also significant nondynamic character. We call this the canonical transformation (CT) theory …

The coupled‐cluster (CC) equations including single, double, triple, and quadruple
excitation amplitudes (CCSDTQ) are derived diagramatically, and the complete set of …

There have been assertions in the literature that the variational and unitary forms of coupled
cluster theory lead to the same energy functional. Numerical evidence from previous authors …

The error in the energy of the traditional coupled-cluster (TCC) approach and of several
variants is analyzed in terms of the error δ of the cluster operator S. A key feature of this …

We present the first application of the Rayleigh–Ritz variational procedure to the coupled
cluster doubles trial function. The variational approach is applied to the potential surface of …

A generalized version of the multireference coupled-cluster method using a single-reference
formalism, which we presented in an earlier paper, has been implemented. Any number of …

The canonical transformation theory of Yanai and Chan [J. Chem. Phys. 124, 194106
(2006)] provides a rigorously size-extensive description of dynamical correlation in …