Accurate total energies of pseudopotentials

We present high accuracy total energies of pseudo-atoms, i.e, atoms with effective core potentials (ECP). The pseudo-atoms considered are the 1st, 2nd and 3rd-row elements with correlation consistent effective core potentials (ccECP) we constructed. For each element, we perform configuration interaction, coupled-cluster, and quantum Monte Carlo calculations with systematically eliminated/improved errors.
We carry out FCI/CCSDT(Q) calculations with aug-cc-pVnZ (n=3-6) basis set extrapolated to complete basis set limit to obtain highly accurate energies. For these methods, the achieved accuracy in the 1st row is typically 0.1-0.3 mHa, the 2nd row is 0.1-0.2 mHa, and 5-10 mHa in the 3rd row. Wherever possible, we included the kinetic energies obtained from FCI calculations to estimate the smoothness/curvature of the particle density. These accurate total energies will serve as a benchmark for independent calculations as well as the assessment of systematic and methodological errors.