ENERGY-DEPENDENT POTENTIALS DETERMINED BY INVERSION - THE P+ALPHA POTENTIAL UP TO 65 MEV

The iterative perturbative inversion method is extended to determine e xplicitly energy and parity dependent potentials from S matrices speci fied at a series of discrete energies. The energy dependence is insert ed only in the potential magnitude, although enhanced ''energy bite'' techniques allow this approximation to be tested. With a linear energy dependence in both real and imaginary components, S-matrix data for p + alpha scattering is fitted with a single potential for a wide range of energies above the inelastic threshold. The imaginary potential is shown to be parity dependent. The real potential is consistent, in bo th the potential shape and the parity and energy dependence, with pote ntials established for subthreshold energies. The method is also appli ed to resonating group model (RGM) phase shifts for n + O-16 and p + a lpha scattering to give energy and parity dependent potentials in both cases. For p + alpha, a close correspondence is obtained between the RGM and the empirical potentials in both the energy and parity depende nce up to about 65 MeV. For n + O-16, potentials are determined for po sitive and negative energies.