Ingoing-wave Boundary-condition Versus Optical-model Transmission Coefficients - A Systematic Comparison With Particle-emission Data

Evaporative 1,2,3H and 4He yields and energy spectra have been analyzed in the framework of the statistical model in ten heavy-ion reactions, spanning composite systems with 20<56. 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 1H and 4He cross sections, they differ significantly in the prediction of 2H and 3H cross sections. OM transmission coefficients fail in reproducing 2,3H 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.