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.

NUCLEAR REACTIONS Fusion cross sections for ${}_{}{}^1{}_{}{}^{}\mathrm{H}$- and ${}_{}{}^4{}_{}{}^{}\mathrm{He}$-induced reactions are systematized to provide reference values for transmission coefficients. Evaporation spectrum analysis made for ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ from ${}_{}{}^{194}{}_{}{}^{}\mathrm{Hg}$ ($E^{*}=98\mathrm{}$ MeV, $l_{\mathrm{crit}}=45\mathrm{}$).

• Received 21 March 1979

DOI:https://doi.org/10.1103/PhysRevC.21.1261