On the Fermi and Gamow-Teller strength distributions in medium-heavy mass nuclei*

An isospin-self-consistent approach based on the continuum- random-phase approximation (CRPA) is applied to describe the Fermi and Gamow-Teller strength distributions within a wide excitation-energy interval. To take into account nucleon pairing in open-shell nuclei, we formulate in isospin-self-consistent version of the proton-neutron-quasiparticle (pn-QCRPA) approach by incorporating the BCS model into the CRPA method. The isospin and configurational splittings of the Gamow-Teller giant resonance are analyzed in single-open-shell nuclei. The calculation results obtained for the Bi-208, Nb-90, and Sb isotopes are compared with the available experimental data. (C) 2003 MAIK Nauka/Interperiodica.