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S. Gupta, B. Meyer (Clemson University)
26Al has a lifetime of only 0.7 Myr against beta decay and serves as an important tracer of galactic chemical evolution. However, it has a low-lying metastable state at 0.228 MeV whose decay to the ground state is inhibited by a high difference in angular momentum between those two states. In such situations, it has been customary to assume a thermal population of excited states and utilize the Hauser-Feshbach formalism to compute beta-decay rates. We present a new technique that follows the non-equilibrium evolution of the nucleus by splitting its excited states into two ensembles instead. This allows us to incorporate as many excited states as we wish into our nucleosynthesis network while simultaneously working with only two effective "species". Effective beta decay rates of 26Al obtained using our technique are used in freezeout calculations that are appropriate to a variety of possible nucleosynthesis environments.