Molecular resonance effects in heavy ion excitation functions

Abstract

The inelastic and fusion excitation functions are analyzed using an interference mechanism between the barrier and internal waves of the heavy ion optical potential. The undamped overlapping molecular resonances are found to be the main dynamical mechanism for the gross oscillations in the excitation function. Our result suggests a rather interesting correlation between the total reaction excitation and the direct surface reaction excitation function. Its origin may be understood as follows: At the resonance, the wave function is pulled into the nuclear interior, and thus, the total reaction cross section is at maximum. The direct surface reaction is, however, shifted by a small phase difference near the surface region. This picture should be valid in the case of overlapping molecular resonance of the heavy ion systems. Good agreement between calculated and experimental inelastic and fusion excitation functions for $^{12}\mathrm{C}$+ $^{12}\mathrm{C}$ and $^{16}\mathrm{O}$+ $^{16}\mathrm{O}$ is obtained.