Ingoing-wave boundary condition versus optical model transmission coefficients: A systematic comparison with particle emission data.

Abstract

Evaporative $^{1,2,3}\mathrm{H}$ and $^{4}\mathrm{He}$ yields and energy spectra have been analyzed in the framework of the statistical model in ten heavy-ion reactions, spanning composite systems with 20Z56. Transmission coefficients derived from the ingoing-wave boundary condition (IWBCM) or optical models (OM) have been used in the calculations. The effect of using different values of deformation parameters, level-density parameter a and radii of the real part of the transmission coefficient potentials has been investigated. Except for the low-energy side of the proton spectra, the shape of energy spectra are reasonably well reproduced by both sets of transmission coefficients. While the two models are essentially equivalent for $^{1}\mathrm{H}$ and $^{4}\mathrm{He}$ cross sections, they differ significantly in the prediction of $^{2}\mathrm{H}$ and $^{3}\mathrm{H}$ cross sections. OM transmission coefficients fail in reproducing $^{2,3}\mathrm{H}$ cross sections, unless no standard parameters are used, while IWBCM transmission coefficients provide a good overall agreement. The failure of the OM is ascribed to the inclusion of nonfusion reactions in the inverse process.