Journal ArticleDOI
Size-extensive effective Hamiltonian formalisms using quasi-Hilbert and quasi-Fock space strategies with incomplete model spaces
TLDR
In this paper, an open-shell coupled cluster (CC) theory is developed using an incomplete model space (IMS) that works entirely within one particular n-valence Hilbert space sector.About:
This article is published in Chemical Physics Letters.The article was published on 1989-11-10. It has received 72 citations till now. The article focuses on the topics: Rigged Hilbert space & Fock space.read more
Citations
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Journal ArticleDOI
Multireference nature of chemistry: the coupled-cluster view.
Journal ArticleDOI
A state-specific multi-reference coupled cluster formalism with molecular applications
TL;DR: A state-specific coupled cluster method based on a reference function composed of determinants spanning a complete active space (CAS) that is expected to provide a uniform description over a wide range of molecular geometries.
Book ChapterDOI
State-Specific Multi-Reference Coupled Cluster Formulations: Two Paradigms
TL;DR: In this article, two alternative paradigms for multi-reference coupled cluster (MRCC) are discussed, the decontracted description and the contracted description, where the combining coefficients appearing in the reference function have to remain frozen in the equations for the cluster amplitudes.
Journal ArticleDOI
Molecular Applications of a Size-Consistent State-Specific Multireference Perturbation Theory with Relaxed Model-Space Coefficients.
TL;DR: The results indicate the smooth performance of the state-specific perturbative formalisms in and around the region of intruders in the PES, indicating their suitability in bypassing intruders.
Journal ArticleDOI
State‐specific multireference coupled‐cluster theory
TL;DR: Although a final and generally accepted multireference CC theory is still lacking, it is emphasized that recent developments render the new MRCC schemes useful tools for solving chemical problems.
References
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Journal ArticleDOI
Coupled-cluster method for multideterminantal reference states
TL;DR: In this paper, a general coupled-cluster method valid for arbitrary multideterminantal reference states is formulated and the resulting cluster expansion for the wave function is a generalization of that introduced by Silverstone and Sinano and applied by Sinano\ifmmode \check{g}else \v{g}\fi{}lu and collaborators.
Journal ArticleDOI
Group theoretical approach to the configuration interaction and perturbation theory calculations for atomic and molecular systems
TL;DR: In this paper, a formalism for the generation of spin-symmetry adapted configuration interaction (CI) matrices of the N −electron atomic or molecular systems, described by nonrelativistic spin-independent Hamiltonians, is presented.
Journal ArticleDOI
On the connectivity criteria in the open-shell coupled-cluster theory for general model spaces
TL;DR: In this article, the authors study the open-shell coupled-cluster theories and examine the current theoretical status regarding the existence or non-existence of a linked-clusters theorem, ensuring the connectedness of the cluster amplitudes and the effective Hamiltonian.
Journal ArticleDOI
The description of N2 and F2 potential energy surfaces using multireference coupled cluster theory
TL;DR: In this article, the ground state potential energy surfaces (PES) for diatomic nitrogen and fluorine were examined using a version of the linearized multireference coupled cluster method (MR•LCCM).
Journal ArticleDOI
Quantum chemistry in Fock space. I. The universal wave and energy operators
TL;DR: In this paper, the wave operator W and the energy operator L were constructed in terms of perturbation theory both in the strictly degenerate and the quasidegenerate version.
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Coupled-cluster method for multideterminantal reference states
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