Continuum fluid dynamics and RPA for giant resonances

Under the restriction of irrotational flow the macroscopic fluid-dynamical (FD) theory of giant resonances based on the generalized scaling approach can be used to calculate excitations in the continuum. For this purpose a self-consistent description of the ground state with correct asymptotic properties for large r is required. Starting with a spherical Hartree-Fock ground state obtained from a simple density-dependent force the results (strength functions, velocity fields and transition densities) for FD and self-consistent RPA are systematically compared. The best agreement is obtained for high-lying collective states (in particular the isovector monopole) which are generated by strong residual particle-hole interactions. The significance of transverse components of the scaling field is studied by comparing polarizability sum rules msub(-1) in the different models. (orig.)