Left‐eigenstate completely renormalized equation‐of‐motion coupled‐cluster methods: Review of key concepts, extension to excited states of open‐shell systems, and comparison with electron‐attached and ionized approaches

Piecuch, Piotr; Gour, Jeffrey R.; Włoch, Marta

doi:10.1002/qua.22367

Cited by 129 publications

(153 citation statements)

References 210 publications

(534 reference statements)

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“…[34]. Equation-of-motion methods (see [26,27] for recent reviews) avoid these problems as they exhibit the transparency and computational simplicity of single-reference coupled-cluster theory.…”

Section: Coupled-cluster Theory and Equations-of-motion For Nucleimentioning

confidence: 99%

“…The operatorR µ , and the energies E µ of the states of interest solve the eigenvalue problem [4,[23][24][25][26][27] (HR…”

Section: Coupled-cluster Theory and Equations-of-motion For Nucleimentioning

confidence: 99%

“…Within the EOM-CC methods, the equations for excited states and one particle attached/removed are well known in quantum chemistry [4,[23][24][25][26][27], and have also been applied to atomic nuclei [28][29][30][31]. However, the corresponding equations for two particle attached/removed have seen very few applications in quantum chemistry [32,33] and are new in nuclear physics.…”

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confidence: 99%

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Toward open-shell nuclei with coupled-cluster theory

et al. 2011

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We develop a new method based on equation-of-motion coupled-cluster theory to describe properties of open-shell nuclei with A ± 2 nucleons outside a closed shell. We perform proof-of-principle calculations for the ground states of the helium isotopes 3−6 He and the first excited 2 + state in 6 He. The comparison with exact results from matrix diagonalization in small model spaces demonstrates the accuracy of the coupled-cluster methods. Three-particle-one-hole excitations of 4 He play an important role for the accurate description of 6 He. For the open-shell nucleus 6 He, the computational cost of the method is comparable with the coupled-cluster singles-and-doubles approximation while its accuracy is similar to coupled-cluster with singles, doubles and triples excitations.

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Section: Coupled-cluster Theory and Equations-of-motion For Nucleimentioning

confidence: 99%

“…The operatorR µ , and the energies E µ of the states of interest solve the eigenvalue problem [4,[23][24][25][26][27] (HR…”

Section: Coupled-cluster Theory and Equations-of-motion For Nucleimentioning

confidence: 99%

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confidence: 99%

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Toward open-shell nuclei with coupled-cluster theory

et al. 2011

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“…[57] for the case of two-body Hamiltonians and those presented in Refs. [60,61,63] in the more general CR-CC(2,3) context, which help us to identify additional terms in the equations due to the 3N forces, we derive the ΛCCSD(T)-style triples energy correction for three-body Hamiltonians which we subsequently apply to the medium-mass closed-shell nuclei 16 O, 24 O, and 40 Ca. By comparing the CCSD and ΛCCSD(T) binding energies obtained with the explicit treatment of 3N interactions with their counterparts obtained within the NO2B approximation, we quantify the contributions of the residual 3N interactions that are neglected in the NO2B approximation at two different CC-theory levels, with and without the connected triply excited clusters.…”

Section: Introductionmentioning

confidence: 99%

Extension of coupled-cluster theory with a noniterative treatment of connected triply excited clusters to three-body Hamiltonians

et al. 2013

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We generalize the coupled-cluster (CC) approach with singles, doubles, and the non-iterative treatment of triples termed ΛCCSD(T) to Hamiltonians containing three-body interactions. The resulting method and the underlying CC approach with singles and doubles only (CCSD) are applied to the medium-mass closed-shell nuclei 16 O, 24 O, and 40 Ca. By comparing the results of CCSD and ΛCCSD(T) calculations with explicit treatment of three-nucleon interactions to those obtained using an approximate treatment in which they are included effectively via the zero-, one-, and two-body components of the Hamiltonian in normal-ordered form, we quantify the contributions of the residual three-body interactions neglected in the approximate treatment. We find these residual normal-ordered three-body contributions negligible for the ΛCCSD(T) method, although they can become significant in the lower-level CCSD approach, particularly when the nucleon-nucleon interactions are soft.

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“…Zero point energies are obtained at the same level. Energies are obtained using the completely renormalized coupled cluster singles and doubles with perturbative triples theory called CR-CC (2,3), available in both closed shell [13] and spin-restricted open shell [14,15] forms. These final energy calculations used the larger basis set, namely aug-ccpVTZ [12].…”

Section: Gas Phase Decomposition Of N 2 Hmentioning

confidence: 99%

The Decomposition of Hydrazine in the Gas Phase and over an Iridium Catalyst

Schmidt

Gordon

2013

Zeitschrift Für Physikalische Chemie

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Hydrazine / Gas Phase / Ir Catalyst / Quantum ChemistryHydrazine is an important rocket fuel, used as both a monopropellant and a bipropellant. This paper presents theoretical results to complement the extensive experimental studies of the gas phase and Ir catalyzed decompositions involved in the monopropellant applications of hydrazine. Gas phase electronic structure theory calculations that include electron correlation predict that numerous molecular and free radical reactions occur within the same energy range as the basic free radical pathways: NN bond breaking around 65 kcal/mol and NH bond breaking around 81 kcal/mol. The data suggest that a revision to existing kinetics modeling is desirable, based on the energetics and the new elementary steps reported herein. A supported Ir 6 octahedron model for the Shell 405 Iridium catalyst used in thrusters was developed. Self-Consistent Field and electron correlation calculations (with core potentials and associated basis sets) find a rich chemistry for hydrazine on this catalyst model. The model catalyst provides dramatically lower NN and NH bond cleavage energies and an even smaller barrier to breaking the NH bond by NH 2 abstractions. Thus, the low temperature decomposition over the catalyst is interpreted in terms of consecutive NH 2 abstractions to produce ammonia and nitrogen. The higher temperature channel, which has hydrogen and nitrogen products, may be due to a mixture of two mechanisms. These two mechanisms are successive NH cleavages with surface H + H recombinations, and the same type of assisted H 2 eliminations found to occur in the gas phase part of this study.

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Left‐eigenstate completely renormalized equation‐of‐motion coupled‐cluster methods: Review of key concepts, extension to excited states of open‐shell systems, and comparison with electron‐attached and ionized approaches

Cited by 129 publications

References 210 publications

Toward open-shell nuclei with coupled-cluster theory

Toward open-shell nuclei with coupled-cluster theory

Extension of coupled-cluster theory with a noniterative treatment of connected triply excited clusters to three-body Hamiltonians

The Decomposition of Hydrazine in the Gas Phase and over an Iridium Catalyst

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