Barrier to complete fusion forHe4andH1and that for evaporation fromHg194

A reference set of transmission coefficients for ${}_{}{}^1{}_{}{}^{}\mathrm{H}$ and ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ reactions is obtained by systematic fits to data for fusion cross sections. Comparisons to other sets, obtained from elastic scattering data, show some significant differences. A comparison is made of calculated to measured evaporation spectra for ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ from ${}_{}{}^{194}{}_{}{}^{}\mathrm{Hg}$ ($E^{*}=98\mathrm{}$ MeV, $l_{\mathrm{crit}}=45\mathrm{}$). There appears to be a significant reduction in the barrier to evaporation for this excited nucleus.