A new generation of effective core potentials from correlated calculations: 3rd row main group

Recently, we have developed a new generation of effective core potentials (ECP) using valence energy isospectrality with explicitly correlated all-electron excitations and norm-conservation criteria. We extend our correlation consistent effective core potentials (ccECP) to 3rd row main group elements. For K and Ca, we use a Ne core and for the 4p elements we utilize large core potentials with 3d-electrons included in the core and with 4s and 4p in the valence shell. We also incorporate relativity including averaged spin-orbit effects. Our ccECPs reproduce all-electron spectra within about chemical accuracy ≈ 0.05 eV. The transferability of ccECPs is tested on corresponding monohydride and monoxide molecules in a wide range of binding geometries. The ccECPs include also optimized valence basis sets and additional comparisons with previously constructed ECPs.