High-Frequency Part of Giant Resonances

Abstract

The fully self-consistent random-phase-approximation response of ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ to the operator $j_J\left(q\mathcal{r}\right)$ is calculated by using the $D1\mathrm{}$ density-dependent effective interaction and studied as a function of the momentum transfer $q$. Corresponding energy-weighted sum rules are evaluated. A striking $q$ dependence is found for low multipoles, and the high-frequency part of the response function is conjectured to be responsible for recently observed resonantlike structures in heavy ion collisions.