A study of the dense Uniform Electron Gas with high orders of Coupled Cluster
Accepted version
Peer-reviewed
Repository URI
Repository DOI
Change log
Authors
Abstract
We investigate the accuracies of different coupled cluster levels in a finite model solid, the 14 electron spin- non-polarised uniform electron gas. For densities between rs = 0.5 a0 and rs = 5 a0 , we calculate ground state correlation energies with stochastic coupled cluster ranging from coupled cluster singles and doubles (CCSD) to coupled cluster including all excitations up to quintuples (CCSDTQ5). We find the need to add triple excitations for an accuracy of 0.01eV/electron beyond rs = 0.5 a0 . Quadruple excitations start being significant past rs = 3 a0 . At rs = 5 a0 , CCSD gives a correlation energy with a 16% error and CCSDT is in error by 2% compared to the CCSDTQ5 result. CCSDTQ5 gives an energy in agreement with full configuration interaction quantum Monte Carlo results.
Description
Keywords
Journal Title
Conference Name
Journal ISSN
1089-7690
Volume Title
Publisher
Publisher DOI
Sponsorship
EPSRC (1502865)
Royal Society (UF160398)
Engineering and Physical Sciences Research Council (EP/L015552/1)