UC San Diego

Results of shell-model calculations of the Gamow-Teller strength distributions for the (n, p) or electron capture direction are presented for 54Fe → 54Mn, 56Fe → 56Mn, 56Ni → 56Co, 60Fe → 60Mn, and 64Fe → 64Mn. In the cases of 56Fe, 60Fe, and 64Fe calculations were performed on both the ground and first excited states. These and similar transitions are characterized by large amounts of Gamow-Teller strength at low excitation energy in the daughter nuclei. The question of quenching in the (n, p) direction remains open. It is expected that the late stages of presupernova stellar evolution (before neutron shell blocking) will depend on the character and distribution of Gamow-Teller strengths for electron capture transitions such as these. © 1985.