Linearized Coupled Cluster Corrections to Antisymmetrized Product of Strongly Orthogonal Geminals: Role of Dispersive Interactions

Zoboki, Tamás; Szabados, Ágnes; Śurján, Péter R.

doi:10.1021/ct400138m

Cited by 52 publications

(60 citation statements)

References 87 publications

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“…A different, computationally feasible approach suitable for strongly-correlated systems uses seniority-zero wavefunctions to describe the static/nondynamic part of the electron correlation en-ergy. [31][32][33][34][35][36][37][38][39][40][41][42][43][44] The missing dynamic electron correlation effects are included a posteriori in these ansätze using, for instance, many-body perturbation theory [45][46][47], coupled-cluster theory [48][49][50][51][52], extended random phase approximation [53], and density functional theory (DFT) corrections [54,55].…”

Section: Introductionmentioning

confidence: 99%

Benchmark of Dynamic Electron Correlation Models for Seniority-Zero Wave Functions and Their Application to Thermochemistry

Boguslawski

Tecmer

2017

J. Chem. Theory Comput.

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Wavefunctions restricted to electron-pair states are promising models to describe static/nondynamic electron correlation effects encountered, for instance, in bond-dissociation processes and transition-metal and actinide chemistry. To reach spectroscopic accuracy, however, the missing dynamic electron correlation effects that cannot be described by electron-pair states need to be included a posteriori. In this article, we extend the previously presented perturbation theory models with an Antisymmetric Product of 1-reference orbital Geminal (AP1roG) reference function that allow us to describe both static/nondynamic and dynamic electron correlation effects. Specifically, our perturbation theory models combine a diagonal and off-diagonal zero-order Hamiltonian, a single-reference and multi-reference dual state, and different excitation operators used to construct the projection manifold. We benchmark all proposed models as well as an a posteriori linearized coupled cluster correction on top of AP1roG against CR-CCSD(T) reference data for reaction energies of several closed-shell molecules that are extrapolated to the basis set limit. Moreover, we test the performance of our new methods for multiple bond breaking processes in the N2, C2, and BN dimers against MRCI-SD and MRCI-SD+Q reference data. Our numerical results indicate that the best performance is obtained from a linearized coupled cluster correction as well as second-order perturbation theory corrections employing a diagonal and off-diagonal zero-order Hamiltonian and a single-determinant dual state. These dynamic corrections on top of AP1roG allow us to reliably model molecular systems dominated by static/nondynamic as well as dynamic electron correlation.

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Section: Introductionmentioning

confidence: 99%

Benchmark of Dynamic Electron Correlation Models for Seniority-Zero Wave Functions and Their Application to Thermochemistry

Boguslawski

Tecmer

2017

J. Chem. Theory Comput.

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“…This is the well-known intruder state problem due to quasi-degeneracies in the frontier orbitals, from which also many other PT methods suffer. [18,22,23] A remedy to this might be the use of unrestricted orbitals, which will lead to improved single-reference energies for bond distances > 1.7Å.…”

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confidence: 99%

Simple and inexpensive perturbative correction schemes for antisymmetric products of nonorthogonal geminals

Limacher

Ayers

Johnson

et al. 2014

Phys. Chem. Chem. Phys.

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A new multireference perturbation approach has been developed for the recently proposed AP1roG scheme, a computationally facile parametrization of an antisymmetric product of nonorthogonal geminals. This perturbation theory of second-order closely follows the biorthogonal treatment from multiconfiguration perturbation theory as introduced by Surjan et al., but makes use of the additional feature of AP1roG that the expansion coefficients within the space of closed-shell determinants are essentially correct already, which further increases the predictive power of the method. Building upon the ability of AP1roG to model static correlation, the perturbation correction accounts for dynamical electron correlation, leading to absolute energies close to full configuration interaction results. Potential surfaces for multiple bond dissociation in H2O and N-2 are predicted with high accuracy up to bond breaking. The computational cost of the method is the same as that of conventional single-reference MP2

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“…When more bonds are involved in a dissociation process (or in case of multiplebond dissociation), the energy formula of Eq. (9) was found to perform well only around equilibrium [14]. As Fig.…”

Section: Perturbing Singlet Geminalsmentioning

confidence: 74%

“…Similarly to the above written dispersive-like excitations [14], cluster operators for other types have to be considered, including those which transfer one or two electrons between geminals.…”

Section: Perturbing Singlet Geminalsmentioning

confidence: 99%

“…In cases where single-reference states are inappropriate, the theory of antisymmetrized product of strongly orthogonal geminals offers an interesting alternative [13][14][15][16][17][18][19]. This method is a generalization of the Hartree-Fock scheme in the sense that the antisymmetrized one-electron orbitals used in the latter are replaced by two-electron functions (geminals) :…”

Section: Introductionmentioning

confidence: 99%

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Role of triplet states in geminal-based perturbation theory

2015

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Linearized Coupled Cluster Corrections to Antisymmetrized Product of Strongly Orthogonal Geminals: Role of Dispersive Interactions

Cited by 52 publications

References 87 publications

Benchmark of Dynamic Electron Correlation Models for Seniority-Zero Wave Functions and Their Application to Thermochemistry

Benchmark of Dynamic Electron Correlation Models for Seniority-Zero Wave Functions and Their Application to Thermochemistry

Simple and inexpensive perturbative correction schemes for antisymmetric products of nonorthogonal geminals

Role of triplet states in geminal-based perturbation theory

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