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arXiv · 1310.6059

Many-body quantum chemistry for the electron gas: convergent perturbative theories

James J. Shepherd·Andreas Grüneis
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Abstract

We investigate the accuracy of a number of wavefunction based methods at the heart of quantum chemistry for metallic systems. Using Hartree-Fock as a reference, perturbative (Møller-Plesset, MP) and coupled cluster (CC) theories are used to study the uniform electron gas model. Our findings suggest that non-perturbative coupled cluster theories are acceptable for modelling electronic interactions in metals whilst perturbative coupled cluster theories are not. Using screened interactions, we propose a simple modification to the widely-used coupled-cluster singles and doubles plus perturbative triples method (CCSD(T)) that lifts the divergent behaviour and is shown to give very accurate correlation energies for the homogeneous electron gas.

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James J. Shepherd, Andreas Grüneis. 2013-10-22. Many-body quantum chemistry for the electron gas: convergent perturbative theories. https://doi.org/10.1103/physrevlett.110.226401

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