FULLY-CORRELATED MULTIELECTRON HIDDEN CROSSINGS THEORY Predrag S. Krstic*, Gary Bent+ and David R. Schultz* *Physics Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA +Physics Department, University of Connecticut, CT, USA A previously developed multielectron-multicenter hidden crossings theory for treatment of slow collisions involving ions and atoms was based on the Unrestricted Hartree-Fock (UHF) and the single-excited-electron Configuration Interaction (SCI) methods, both obtained by analytical extension of the internuclear distance R into the complex plane. Here we further generalize the method by allowing all-electron excitations while optimizing Slater-type primitives in each step in the complex R-plane. We apply it to describe ionization of He by slow protons and antiprotons and excitation of H in slow collision with H.