In reply to Eric Walker's message of Fri, 5 Jul 2013 19:11:47 -0700: Hi, [snip] >On Fri, Jul 5, 2013 at 6:36 PM, <[email protected]> wrote: > >>You won't get fission from the mid range elements by adding a single >> nucleon. >> >That doesn't happens at the ends of the periodic table. >> >> That should read:- "That only happens at the ends of the periodic table." >> > >What are the approximate upper and lower bounds? > >Eric
The lightest heavy element/isotope is somewhere in the Actinides. The heaviest light element is difficult to determine because the p(Z,alpha)Z-1 reactions you find on the Inet, only happen at high proton energies (see EXFOR). Consequently the results are likely to be different to those resulting from an electron shielded reaction. (The kinetic energy of the original proton has to go somewhere, so there is more total energy available to the reaction, probably resulting in different branching ratios.) However this notion of mine is based on neutron addition, and things may be a bit different with proton addition, because with the latter an extra charge is being added to the nucleus, which may make it easier to expel an alpha particle. Furthermore, the branching ratio of electron shielded reactions will also depend on what other particles are (or not) available to share the resultant fusion energy (e.g. shrunken electrons &/or additional protons). See http://aether.lbl.gov/www/tour/elements/stellar/stellar_a.html for the current model of what happens in stars. (The only example I could think of where fusion reactions happen naturally). Regards, Robin van Spaandonk http://rvanspaa.freehostia.com/project.html
