Very recently, we have introduced correlation consistent effective core potentials (ccECPs) derived from many-body approaches with the main target being its use in explicitly correlated methods but also in mainstream approaches. The ccECPs are based on reproducing excitation energies for a subset of valence states, i.e., achieving a near-isospectrality between the original and pseudo Hamiltonians. In addition, binding curves of dimer molecules have been used for refinement and overall improvement of transferability over a range of bond lengths. Here we apply similar ideas to the second row elements and study several aspects of the constructions in order to find the optimal (or nearly-optimal) solutions within the chosen ECP forms with 3s,3p valence space (Ne-core). New constructions exhibit accurate low-lying atomic excitations and equilibrium molecular bonds (on average within ≈0.03 eV and 3 m\AA), however, the errors for Al and Si oxide molecules at short bond lengths are notably larger for both ours and existing ECPs. Assuming this limitation, our ccECPs show a systematic balance between the criteria of atomic spectra accuracy and transferability for molecular bonds. In order to provide another option with much higher uniform accuracy, we also construct He-core ECPs for the whole row with typical discrepancies of ≈ 0.01 eV or smaller.
@article{arxiv.1805.00607,
title = {New generation of effective core potentials from correlated calculations: 2nd row elements},
author = {M. Chandler Bennett and Guangming Wang and Abdulgani Annaberdiyev and Cody A. Melton and Luke Shulenburger and Lubos Mitas},
journal= {arXiv preprint arXiv:1805.00607},
year = {2018}
}