Green's function coupled cluster formulations utilizing extended inner excitations

Abstract

In this paper we analyze new approximations of the Green's function coupled cluster (GFCC) method where locations of poles are improved by extending the excitation level of inner auxiliary operators. These new GFCC approximations can be categorized as GFCC-i($n,m$) method, where the excitation level of the inner auxiliary operators ($m$) used to describe the ionization potentials and electron affinities effects in the $N$$-$1 and $N$+1 particle spaces is higher than the excitation level ($n$) used to correlate the ground-state coupled cluster wave function for the $N$-electron system. Furthermore, we reveal the so-called "$n$+1" rule in this category (or the GFCC-i($n$,$n$+1) method), which states that in order to maintain size-extensivity of the Green's function matrix elements, the excitation level of inner auxiliary operators $X_p(\omega )$ and $Y_q(\omega )$ cannot exceed $n$+1. We also discuss the role of the moments of coupled cluster equations that in a natural way assures these properties. Our implementation in the present study is focused on the first approximation in this GFCC category, i.e. the GFCC-i(2,3) method. As our first practice, we use the GFCC-i(2,3) method to compute the spectral functions for the N${}_2$ and CO molecules in the inner and outer valence regimes. In comparison with the GFCCSD results, the computed spectral functions from the GFCC-i(2,3) method exhibit better agreement with the experimental results and other theoretical results, particularly in terms of providing higher resolution of satellite peaks and more accurate relative positions of these satellite peaks with respect to the main peak positions.

arXiv comment27 pagers, 5 figures

References in corpus (19)

• Electronic Structure Calculations with Dynamical Mean-Field Theory: A Spectral Density Functional Approach
• A continuous-time solver for quantum impurity models
• Quasiparticle Self-Consistent GW Theory
• Renormalization of Molecular Electronic Levels at Metal-Molecule Interfaces
• All-electron self-consistent GW approximation: Application to Si, MnO, and NiO
• Hybridization expansion impurity solver: General formulation and application to Kondo lattice and two-orbital models
• Dynamical mean-field theory from a quantum chemical perspective
• Truncated Configuration Interaction expansions as solvers for correlated quantum impurity models and dynamical mean field theory
• Optical potential from first principles
• Towards ab initio self-energy embedding theory in quantum chemistry
• Systematically improvable multi-scale solver for correlated electron systems
• Second-order Green's function perturbation theory for periodic systems
• Spectral Functions of the Uniform Electron Gas via Coupled-Cluster Theory and Comparison to the $GW$ and Related Approximations
• Generalized self-energy embedding theory
• Review of biorthogonal coupled cluster representations for electronic excitation
• Non-iterative triples excitations in equation-of-motion coupled-cluster theory for electron attachment with applications to bound and temporary anions
• Band structures in coupled-cluster singles-and-doubles Green's function (GFCCSD)
• Comparison of Green's functions for transition metal atoms using self-energy functional theory and coupled-cluster singles and doubles (CCSD)
• Quasiparticle energy spectra of isolated atoms from coupled-cluster singles and doubles (CCSD): Comparison with exact CI calculations

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