2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/170920Postulates of the quantum atomistic solid-state theory (QUASST) have been presented. QUASST is an extension of the crystal-field theory and is applicable to compounds containing open-shell 3d, 4f and 5f atoms. QUASST points out the existence in a solid of the atomic-like discrete electronic structure determined by the crystal- field and spin-orbit interactions. This approach unifies the description of 3d and 4f ions and allows to bridge the atomic physics and the solid-state physics.9 pages in RevTex, no figureStrongly Correlated Electronstext