2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/85125We propose simple analytic, non-orthogonal but selectively orthogonalizable, generalized Laguerre type atomic orbitals, providing clear physical interpretation and near equivalent accuracy with numerical multi-configuration self-consistent field, to atomic configuration interaction calculations. By analyzing the general Eckart theorem we use their simple interpretation, via a thorough investigation in orbital space, to estimate, for the first time (the exact value being, or considered, unknown), an ab-initio energy uncertainty, i.e. proximity to the exact energy, for several excited atomic states known to have the danger to suffer from variational collapse.9 pages, 1 figureAtomic PhysicsComputational Physicstext