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Coupled cluster methods are widely regarded as the gold standard ofcomputational quantum chemistry as they are perceived to offer the bestcompromise between computational cost and a high-accuracy resolution of theground state eigenvalue of the electronic Hamiltonian -- an unbounded,self-adjoint operator acting on a Hilbert space of antisymmetric functions thatdescribes electronic properties of molecular systems. The present contributionis the second in a series of two articles where we introduce a new numericalanalysis of the single-reference coupled cluster method based on theinvertibility of coupled cluster Fr\'echet derivative. In this contribution, westudy discretisations of the single-reference coupled cluster equations basedon a prior mean-field (Hartree-Fock) calculation. We show that under somestructural assumptions on the associated discretisation spaces and assumingthat the discretisation is fine enough, the discrete coupled cluster equationsare locally well-posed, and we derive a priori and residual-based a posteriorierror estimates for the discrete coupled cluster solutions. Preliminarynumerical experiments indicate that the structural assumptions that we imposefor our analysis can be expected to hold for several small molecules and thetheoretical constants that appear in our error estimates are an improvementover those obtained from earlier approaches.

Analysis of the Single Reference Coupled Cluster Method for Electronic Structure Calculations: The Discrete Coupled Cluster Equations