The observation and prediction of unusually depressed first excited 2^+_1
states in even-A neutron - rich isotopes of semi-magic Sn above 132Sn provide
motivations for reviewing the problems related to the nuclear astrophysics in
general. In the present work, the beta-decay rates of the exotic even Sn
isotopes (134,136Sn) above the 132Sn core have been calculated as a function of
temperature (T). In order to get the necessary ft values, B(GT) values
corresponding to allowed Gamow Teller (GT-) beta-decay have been theoretically
calculated using shell model. The total decay rate shows decrease with
increasing temperature as the ground state population is depleted and
population of excited states with slower decay rates increases. The abundance
at each Z value is inversely proportional to the decay constant of the waiting
point nucleus for that particular Z. So the increase in half-life of isotopes
of Sn, like 136Sn, might have substantial impact on the r-process
nucleosynthesis.Comment: 4th International Workshop on Nuclear Fission and Fission Product
Spectroscopy, CEA Cadarache, May 13 - 16, 2009, 4 pages, 2 figure
