2024/02/24 by Nikolaos Masios, Masios, Nikolaos, Felix Hummel +5
Chemical Engineering · Materials Science · Physics and Astronomy · #Advanced Chemical Physics Studies #Catalysis and Oxidation Reactions #Catalytic Processes in Materials Science #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci)
paper · pdf · doi:10.48550/arxiv.2402.15907
openalex publication_date 2024/02/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/03
We investigate the convergence of coupled-cluster correlation energies and related quantities with respect to the employed basis set size for the uniform electron gas to gain a better understanding of the basis set incompleteness error. To this end, coupled-cluster doubles (CCD) theory is applied to the three dimensional uniform electron gas for a range of densities, basis set sizes and electron numbers. We present a detailed analysis of individual, diagrammatically decomposed contributions to the amplitudes at the level of CCD theory. In particular, we show that only two terms from the amplitude equations contribute to the asymptotic large-momentum behavior of the transition structure factor, corresponding to the cusp region at short interelectronic distances. However, due to the coupling present in the amplitude equations, all decomposed correlation energy contributions show the same asymptotic convergence behavior to the complete basis set limit. These findings provide an additional rationale for the success of a recently proposed correction to the basis set incompleteness error (BSIE) of coupled-cluster theory. Lastly, we examine the BSIE in the coupled-cluster doubles plus perturbative triples [CCD(T)] method, as well as in the newly proposed coupled-cluster doubles plus complete perturbative triples [CCD(cT)] method.