Spreading of the Gamow-Teller Resonance in ⁹⁰Nb and ²⁰⁸Bi

Spreading properties of the Gamow-Teller resonance in ⁹⁰Nb and ²⁰⁸Bi are studied within an approach including the 2p2h configuration mixing and the ground-state correlations beyond the random-phase approximation. The M3Y interaction and single-particle wave functions within the standard harmonic oscillator potential are used in numerical calculations. The single-particle energies around the Fermi surface are replaced with the empirical values or those given by a Woods-Saxon potential. Results obtained provide a reasonable account for recent experimental findings. The extension of the present approach to hot nuclei is also provided.