Theory of relaxation due to spin-exchange collisions

A general method is developed for the evaluation of the relaxation rates due to spin-exchange collisions. For the case where nuclear spin I = $\text{1}\text{2}$, all the relaxation rates are found, account being taken of the hyperfine and Zeeman interactions. The present theory can be applied to the following systems: (1) H + H, (2) H + a different electron-spin-$\text{1}\text{2}$ atom, and (3) H + H₂.