Nuclear magnetic resonance of anti-parallel spin neutrons (of total spin zero for the neutron-spin pair), plus a proton of spin . Therefore, the tritium total nuclear spin value is again , just like for the simpler, abundant hydrogen isotope, H nucleus (the "proton"). The NMR absorption frequency for tritium is also similar to that of H. In many other cases of "non-radioactive" nuclei, the overall spin is also non-zero. For example, the nucleus has an overall spin value . A non-zero spin formula_2 is always associated with a non-zero magnetic dipole moment, formula_3, via the relation formula_4 where "γ" is the gyromagnetic ratio.
Isotope geochemistry and origins of Earth systems. They are particularly useful to understand mixing processes between different components, because (heavy) radiogenic isotope ratios are not usually fractionated by chemical processes. Radiogenic isotope tracers are most powerful when used together with other tracers: The more tracers used, the more control on mixing processes. An example of this application is to the evolution of the Earth's crust and Earth's mantle through geological time. Lead has four stable isotopes - Pb, Pb, Pb, Pb and one common radioactive isotope Pb with a half-life of ~53,000 years. Lead is created in the Earth via decay of