ISOLATION OF THE REGIONS OF POTENTIAL SIGNIFICANCE IN FINE-STRUCTURE TRANSITIONS USING ADIABATIC AND FUNCTIONAL SENSITIVITY ANALYSES - A COMPARATIVE INVESTIGATION WITH APPLICATIONS TO NA(P-2(1 2))+HE-]NA(P-2(3/2))+HE AND NA(P-2(1/2))+AR-]NA(P-2(3/2))+AR/

The first-order functional sensitivity densities deltalnsigma1/2-->3/2 (E)/deltalnW\LAMBDA\(R) are employed to assess the role of structure i n the potential-energy curves W0(2SIGMA) and W1(2PI) mediating the fin e-structure transition Na(P-1/2(2)) + He-->Na(P-3/2(2)) + He and Na(P- 1/2(2)) + Ar-->Na(P-3/2(2)) + Ar. The sensitivity density profiles del talnsigma1/2-->3/2(E)/deltalnW\LAMBDA\(R) for the two systems reveal t hat regions of significance differ widely for the 2SIGMA and 2PI curve s. The results suggest that prevalent mechanistic explanations from ad iabatic analyses have limitations in terms of the ultimate significanc e of the identified kinematic coupling over well demarcated radial and angular coupling regions. The functional sensitivity analysis is show n to permit a full deconvolution of the collision cross section's depe ndence on the features in the individual 2SIGMA and 2PI curves as oppo sed to the adiabatic analysis where only the features in [W0(R)-W1(R)] are deemed critical to the collisional outcome.