Gamow--Teller (GT) transitions play an important and consequential role in many astrophysical phenomena. These include, but are not limited to, electron and positron capture rates which determine the fate of massive stars and play an intricate role in the dynamics of core collapse. These GT_\pm transitions rates are the significant inputs in the description of supernova explosions. GT_\pm strength function values are sensitive to the ⁵⁶Ni core excitation in the middle {pf}-shell region and to the size of the model space as well. We used the pn-QRPA theory for extracting the GT strength for ground and excited states of ⁵⁶Ni. We then used these GT strength distributions to calculate the electron {and} positron capture rates which show differences with the earlier calculations. One curious finding of this paper is our enhanced electron capture rates on ⁵⁶Ni at presupernova temperatures. These differences need to be taken into account for the modeling of the early stages of Type II supernova evolution.

PACS numbers: 26.50.+x, 23.40.Bw, 23.40.--s, 21.60.Jz