Molecular-Environment Feedback Improves Superposition-of-Atomic-Potential SCF Guesses.

Self-consistent-field calculations require an inexpensive initial electronic structure that nevertheless reflects the molecular environment. Standard superposition of atomic potentials (SAP) is efficient, but its component potentials describe isolated atoms. We show that the missing environmental information is already encoded in the first molecular SAP density and can be returned through one damped atom-resolved update of the fitted screening potentials. With the feedback strength frozen at 0.25, the intrinsic-atomic-orbital (IAO) realization reduces median density distance by 25.10%, 25.89%, and 25.96% for RHF, PBE, and PBE0 on an independent 80-structure hold-out. IAO charge correlations remain at least 0.99989 from def2-SVP through augmented triple- and quadruple-zeta bases. The original symmetric-Löwdin realization gives the same response direction in compact bases but exposes the expected diffuse-basis pathology. No target-functional information, converged target density, or auxiliary fragment calculation enters either guess.