Semimicroscopic description of basic properties of isoscalar monopole and dipole excitations in medium-mass spherical nuclei

A description of basic properties (strength function, transition density, probabilities of direct nucleonic decays) of isoscalar giant monopole (including an overtone) and dipole resonances in medium-mass spherical nuclei is proposed within a semimicroscopic approach. The approach relies on employing the random-phase approximation and involves taking exactly into account a single-particle continuum and some conditions of partial self-consistency and phenomenologically describing the coupling of states of the particle-hole type to multiquasiparticle configurations. The results of the calculations that were performed for 90Zr, 116,124Sn, 144Sm, and 208Pb nuclei are compared with available experimental data.