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Coupled cluster Green function: Model involving single and double excitations

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TLDR
A key aspect of this work is the determination of the frequency dependent self-energy, Σ(ω), which reveals a diagonally dominate block structure where as the non-local correlation increases, the block size increases proportionally.
Abstract
In this paper, we report on the development of a parallel implementation of the coupled-cluster (CC) Green function formulation (GFCC) employing single and double excitations in the cluster operator (GFCCSD). A key aspect of this work is the determination of the frequency dependent self-energy, Σ(ω). The detailed description of the underlying algorithm is provided, including approximations used that preserve the pole structure of the full GFCCSD method, thereby reducing the computational costs while maintaining an accurate character of methodology. Furthermore, for systems with strong local correlation, our formulation reveals a diagonally dominate block structure where as the non-local correlation increases, the block size increases proportionally. To demonstrate the accuracy of our approach, several examples including calculations of ionization potentials for benchmark systems are presented and compared against experiment.

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Electronic structure and spectroscopy of nucleic acid bases: Ionization energies, ionization-induced structural changes, and photoelectron spectra

TL;DR: Vibrational progressions for the S(0)-D(0) vibronic bands computed within double-harmonic approximation with Duschinsky rotations are compared with previously reported experimental photoelectron spectra and differentiated PIE curves.
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On The Relation Between Equation-of-Motion Coupled-Cluster Theory and the GW Approximation

TL;DR: It is argued that (in molecules) exchange is as important as screening, advocating for a Hartree-Fock reference and second-order exchange in the self-energy.
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GW Vertex Corrected Calculations for Molecular Systems.

TL;DR: Hedin's scheme is solved with the inclusion of the vertex function (GWΓ) for a set of small molecules, and very good agreement with expensive wave function-based methods is obtained for both approximations.
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One-particle many-body Green's function theory: Algebraic recursive definitions, linked-diagram theorem, irreducible-diagram theorem, and general-order algorithms.

TL;DR: The diagrammatic linkedness and thus size-consistency of the one-particle Green's function and self-energy are demonstrated at any perturbation order on the basis of the algebraic recursions in an entirely time-independent (frequency-domain) framework.
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Electronic Structure and Stability of [B12X12]2- (X = F-At): A Combined Photoelectron Spectroscopic and Theoretical Study.

TL;DR: The unusual intrinsic electronic structure of the [B12X12]2- MCAs provides the basis for a molecular level understanding of their observed unique physical and chemical properties and a new paradigm for understanding the properties of these MCAs with not well-separated charges that departs from the prevailing model used for spatially separated charges.
References
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Journal ArticleDOI

A coupled‐cluster based effective Hamiltonian method for dynamic electric polarizabilities

TL;DR: In this article, a coupled-cluster based approach for calculating dynamic polarizabilities is described, where the polarizability is calculated by a strategy that is formally equivalent to a sum over states corresponding to the diagonal representation of a similarity transformed Hamiltonian operator.
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Communication: The description of strong correlation within self-consistent Green's function second-order perturbation theory

TL;DR: In this paper, an implementation of self-consistent Green's function many-body theory within a second-order approximation (GF2) for application with molecular systems is reported, which is done by iterative solution of the Dyson equation expressed in matrix form in an atomic orbital basis.
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UV photoelectron and quantum mechanical characterization of DNA and RNA bases: valence electronic structures of adenine, 1,9-dimethyl-guanine, 1-methylcytosine, thymine and uracil

TL;DR: In this article, the results of the ab initio SCF-MO calculations employing a double zeta 4-31G basis set and HAM/3 semi-empirical calculations have been obtained through the application of Koopmans' theorem.
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Electronic structure and spectroscopy of nucleic acid bases: ionization energies, ionization-induced structural changes, and photoelectron spectra.

TL;DR: In this paper, the authors reported high-level ab initio calculations and single-photon ionization mass spectrometry study of ionization of adenine (A), thymine (T), cytosine (C), and guanine (G).
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The description of strong correlation within self-consistent Green's function second-order perturbation theory

TL;DR: The results show that self-consistent Green's function many-body theory offers a viable route to describing strong correlations while remaining within a computationally tractable single-particle formalism.
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