On Fri, Dec 4, 2015 at 3:07 PM, <[email protected]> wrote: I guess there are some exceptions. :) >
For exothermic 4He + Pd reactions with 1-3 daughters which also occur in nature, I get a count of 269 reactions. If one removes the limitation on unstable daughters, I get a count of 4556 reactions. 4He + 102Pd => 26Mg + 80Kr + 8602 keV 4He + 106Pd => 22Ne + 88Sr + 8464 keV 4He + 104Pd => 4He + 30Si + 74Ge + 8460 keV (Some of the reactions spit a 4He back out.) However try this for the reactions that Iwamura reported. > To get from cesium to praseodymium, we have: 4He + 133Cs => gamma + 137La + 1495 keV 4He + 137La => gamma + 141Pr + 1300 keV To get from strontium to molybdenum, we have: 4He + 88Sr => gamma + 92Zr + 2963 keV 4He + 92Zr => gamma + 96Mo + 2759 keV The case of barium to samarium does appear to be endothermic; e.g., 4He + 137Ba => gamma + 141Ce + 139 keV 4He + 141Ce => gamma + 145Nd + -1579 keV 4He + 145Nd => gamma + 149Sm + -1872 keV Iwamura and the other authors had trouble confirming samarium when they started with 137Ba, although they thought it was probable. It makes sense that this chain would have been attenuated due to the endothermic steps. But if the result was in fact real, it also suggests that the alphas are travelling with ~ 3-9 MeV of energy. :) The actual chains would have been more complex in the case of barium because some of the intermediate steps are unstable. But a more complete analysis shows that several paths that diverge will eventually reconverge on samarium. Eric
