Advanced Charge\nExtended Huckel (CEH) Model\nand a Consistent Adaptive Minimal Basis Set for the Elements <i>Z</i> = 1–103

The Charge Extended Hückel (CEH) model, initially\nintroduced\nfor adaptive atomic orbital (AO) basis set construction (<i>J.\nChem. Phys.</i> <b>2023</b>, 159, 164108), has been significantly\nrevised to enhance accuracy and robustness, particularly in challenging\nelectronic situations. This revision includes an extension toward <i>f</i>-elements, covering actinoids with their <i>f</i>-electrons in the valence space. We present a novel noniterative\napproximation for the electrostatic contribution to the effective\nFock matrix, which substantially improves performance in polar or\ncharged systems. Additionally, the training data set for elements <i>Z</i> = 1–103 has been expanded to encompass even more\nchemically diverse reference molecules as well as dipole moments and\nshell populations in addition to atomic charges. It includes a greater\nvariety of “mindless” molecules (MLMs) as well as more\ncomplex electronic structures through open-shell and highly charged\nspecies. The revised method achieves mean absolute errors for atomic\ncharges <i>q</i> of approximately 0.02 <i>e</i><sup>–</sup> for randomly selected (mostly organic) molecules\nand 0.09 <i>e</i><sup>–</sup> for MLMs, outperforming\nboth classical charge models and established tight-binding methods.\nFurthermore, the revised CEH model has been validated through density\nfunctional theory calculations with the updated adaptive q-vSZP AO\nbasis set on common thermochemical databases. Consistent with the\nextension of the CEH model, q-vSZP has also been variationally optimized\nand tested for elements <i>Z</i> = 58–71 and 87–103.\nThe original versions of both CEH and q-vSZP are now considered deprecated.