Nuclear Spin-Lattice Relaxation in Noncubic or Imperfect Cubic Crystals forI=72 or 92

Detailed calculations of the relaxational behavior of the central resonance line corresponding to transitions between levels $m=\pm \frac{1}{2}$ have been made for $I=\frac{7}{2}$ and $I=\frac{9}{2}$ in noncubic or imperfect cubic crystals. The behavior of the central line depends on the relative values of $\frac{W_1}{W_2}$ and differs considerably in the two special cases which have been considered.