Work

Developments in stochastic coupled cluster theory: The initiator approximation and application to the uniform electron gas

Year: 2016

Type: article

Abstract: We describe further details of the stochastic coupled cluster method and a diagnostic of such calculations, the shoulder height, akin to the plateau found in full configuration interaction quantum Monte Carlo. We describe an initiator modification to stochastic coupled cluster theory and show that initiator calculations can at times be extrapolated to the unbiased limit. We apply this method to the 3D 14-electron uniform electron gas and present complete basis set limit values of the coupled cluster singles and doubles (CCSD) and previously unattainable coupled cluster singles and doubles with perturbative triples (CCSDT) correlation energies for up to r(s) = 2, showing a requirement to include triple excitations to accurately calculate energies at high densities.

Source: The Journal of Chemical Physics

DOI: 10.1063/1.4942173

Authors: James S. Spencer, Alex J. W. Thom

Institutions: Imperial College London, University of Cambridge

Language: English

Topic: Advanced Chemical Physics Studies

Subfield: Atomic and Molecular Physics, and Optics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: green

Funders: Royal Society, Thomas Young Centre

Awards: G11264261, G2697776615