Diagrammatic derivation ofT1for solidH2

A previously discussed diagrammatic technique is used to obtain equations for the nuclear spin self-energy in solid ${\mathrm{H}}_2$ and thus formulas are obtained for $T_1$ and other nuclear spin relaxation times in that system. These formulas are equivalent to those obtained by Ebner and Myles using the Blume-Hubbard formalism. It is thus shown that the diagrammatic technique, the Blume-Hubbard technique, and other, standard techniques yield identical results in lowest order. The fact that these more complicated techniques yield standard results for cases of exponential relaxation is an important check on these formalisms. The resulting relaxation times are then evaluated using previously calculated rotational-angular-momentum correlation functions and the results are compared with experiment and with the results of Ebner and Myles.