Krmpotić, F.Nakayama, K.Galeão, A.Pio [UNESP]2014-05-262014-05-261983-05-16Nuclear Physics, Section A, v. 399, n. 2, p. 478-502, 1983.0375-9474http://hdl.handle.net/11449/63607Recent experimental data on first-forbidden charge-exchange resonances are discussed in the framework of a schematic model. We also evaluate the screening of the weak coupling constants induced by both the giant resonances and the Δ-isobar. It is shown that the last effect does not depend on the multipolarity of the one-particle moment. Due to the same reason, the fraction of the reaction strength pushed up into the Δ-resonance region is always the same regardless of the quantum numbers carried by the excitation. Simple expressions are derived for the dependence of the excitation energies of the first-forbidden giant resonances on the mass number and isospin of the target. The model reproduces consistently both the Gamow-Teller and the first-forbidden resonances. © 1983.478-502engArtigo10.1016/0375-9474(83)90259-2WOS:A1983QS51600011Acesso restrito2-s2.0-46249084400