A PROBE OF DYNAMICAL MODELS USING FUNCTIONAL SENSITIVITY DENSITIES WITH APPLICATION TO HE+ PLUS NE(2P(6))-]HE+ PLUS NE(2P(5)3S) AND LI+I-]LI+ PLUS I-

The functional sensitivity densities delta ln sigma(12)(E)/delta ln V-ii(R) for He+ + Ne(2p(6)) --> He+ + Ne(2p(5)3s) reveal that the collisional excitation cross section sigma(12)(E) is insensitive to the additional diabatic curve V-33 included in some models. The negligible sensitivity sigma(12)(E) to V-33 offers a quantitative validation of the more popular two state model for collisional excitation of Ne by He+. The sensitivity profiles for the collisional ionization Li + I --> Li+ + I- modeled by crossing diabatic curves V-11 (covalent) and V-22 (ionic) shows that the ionization cross section does not depend on inner crossings even when these stem from large distortions in the underlying potential energy curves. The lack of sensitivity to inner crossings establishes the predominant role of the outermost crossing in triggering nonadiabatic transitions.