Method of moments of coupled-cluster equations: a new formalism for designing accurate electronic structure methods for ground and excited states
Title | Method of moments of coupled-cluster equations: a new formalism for designing accurate electronic structure methods for ground and excited states |
Publication Type | Journal Article |
Year of Publication | 2004 |
Authors | Piecuch, P, Kowalski, K, Pimienta, ISO, Fan, P-D, Lodriguito, MD, McGuire}, MJ {, Kucharski, SA, Kuś, T, Musial, M |
Journal | Theoretical Chemistry Accounts: Theory, Computation, and Modeling |
Volume | 112 |
Pagination | 349–393 |
Date Published | 07/2004 |
Keywords | Coupled-cluster theory - Method of moments of coupled-cluster equations - Renormalized coupled-cluster methods - extended coupled cluster theory - Potential energy surfaces |
Abstract | The method of moments of coupled-cluster equations {(MMCC),} which provides a systematic way of improving the results of the standard coupled-cluster {(CC)} and equation-of-motion {CC} {(EOMCC)} calculations for the ground- and excited-state energies of atomic and molecular systems, is described. The {MMCC} theory and its generalized {MMCC} {(GMMCC)} extension that enables one to use the cluster operators resulting from the standard as well as nonstandard {CC} calculations, including those obtained with the extended {CC} {(ECC)} approaches, are based on rigorous mathematical relationships that define the many-body structure of the differences between the full configuration interaction {(CI)} and {CC} or {EOMCC} energies. These relationships can be used to design the noniterative corrections to the {CC/EOMCC} energies that work for chemical bond breaking and potential energy surfaces of excited electronic states, including excited states dominated by double excitations, where the standard single-reference {CC/EOMCC} methods fail. Several {MMCC} and {GMMCC} approximations are discussed, including the renormalized and completely renormalized {CC/EOMCC} methods for closed- and open-shell states, the quadratic {MMCC} approaches, the {CI-corrected} {MMCC} methods, and the {GMMCC} approaches for multiple bond breaking based on the {ECC} cluster amplitudes. |