Overtones of isoscalar giant resonances in medium-heavy and heavy nuclei

A semimicroscopic approach based on both the continuum random-phase-approximation method and a phenomenological treatment of the spreading effect is extended and applied to describe the main properties (particle-hole strength distribution, energy-dependent transition density, partial direct-nucleon-decay branching ratios) of the isoscalar giant dipole, second monopole, and second quadrupole resonances. The abilities of the approach are checked by description of the gross properties of the main-tone resonances. Calculation results obtained for the resonances in a few singly- and doubly-closed-shell nuclei are compared with available experimental data.