RELATIVISTIC THOMAS-FERMI DESCRIPTION OF COLLECTIVE MODES IN DROPLETSOF NUCLEAR-MATTER

Isoscalar collective modes in a relativistic meson-nucleon system are investigated in the framework of the time-dependent Thomas-Fermi metho d. The energies of the collective modes are determined by solving cons istently the dispersion relations and the boundary conditions. The ene rgy weighted sum rule satisfied by the models considered allows the id entification of the giant resonances. The percentage of the energy wei ghted sum rule exhausted by the collective modes is in agreement with experimental data, but the agreement with the energy of the modes depe nds on the model considered.