Half-life for nuclei far from the stability line and structure of the β-decay strength function

Basing on the finite Fermi system theory a method is developed to describe the half-life Tsub(1/2) for short-lived nuclei (Tsub(1/2)<10 s). For a large group of the nuclei the calculation accuracy is analysed for two considered lambda- and BETA-models and it is shown that the mean accuracies in Tsub(1/2) for the known nuclei are 50% and 80%, respectively, which are several times as high as those for the existing calculations using other methods. It is shown that the values of Tsub(1/2) depend substantially on the structure of the strength function for the β decay, determined by the collective isobar states. The mechanism is analysed for a decrease in Tsub(1/2) with rise of the energy Qsub(β) both for β- and β+ decays; in particular, the effect of the Gamov-Teller and analogue resonances in region of the with Z>=N