Empirical and theoretical fusion barriers for 1H and 4He: Connections to evaporation from hot nuclei

Fusion excitation functions for 1H and 4He have been compared to a one-dimensional, barrier-penetration model. In contrast to fusion for heavier nuclei this simple model is completely adequate, except for the statically deformed targed 233U. Empirical barrier heights are obtained and compared to those from two theoretical nuclear potentials. These empirical barriers (from cold reactants) are used as input for calculating evaporation spectra that arise from hot nuclear emitters. The excess of observed low-energy 1H and 4He emission signals information content concerning distortions of the hot nuclei. (orig.)