alpha decay atom atomic mass atomic nucleus atomic number beta decay big bang biogenic substance chemical element chemical symbol chlorine cluster decay deuterium digital object identifier fluorine frederick soddy gamma ray gamma spectroscopy half-life infrared infrared spectroscopy internal conversion isobar isomer isotone isotope analysis isotope separation isotopic labeling isotopic signature isotopologue kinetic isotope effect knolls atomic power laboratory list of particles manhattan project mars mars meteorite mass number mass spectrometry neutron neutron capture nuclear isomer nuclear magnetic resonance nuclear power nuclear weapon nucleosynthesis nuclide periodic table photon physical cosmology protein radiocarbon dating radiometric dating radionuclide reduced mass silac spontaneous fission stable isotope table of nuclides tin