Nuclear Quadrupole Resonance in Rhombic Sulfur and the Quadrupole Moments ofS33andS35

Four closely spaced absorption lines due to nuclear quadrupole resonance of the ${\mathrm{S}}^{33}$ isotope have been observed near 22.9 Mc/sec in a sample of rhombic sulfur, containing this isotope in its natural abundance of 0.74 percent. As the nuclear spin of ${\mathrm{S}}^{33}$ is $\frac{3}{2}$, these lines correspond to the transition $m=\pm \frac{1}{2}\leftrightarrow m=\pm \frac{3}{2}$ and an average quadrupole coupling constant $\frac{e{Q}^{33}{q}_{\mathrm{zz}}}{h}=45.8\mathrm{}$ Mc/sec. The bond structure of the ${\mathrm{S}}_8$ molecule is discussed with respect to the evaluation of $q_{\mathrm{zz}}$, the gradient of the electric field at the site of the nucleus. From the measured coupling constant $e{Q}^{33}{q}_{\mathrm{zz}}$ and the calculated $q_{\mathrm{zz}}$, the value $Q^{33}=-0.050\mathrm{}\times {10}^{-24\mathrm{}}$ ${\mathrm{cm}}^2$ is obtained for the nuclear quadrupole moment of ${\mathrm{S}}^{33}$. With the ratio $\frac{Q^{35}}{Q^{33}}$ known from microwave data, this leads to $Q^{35}=+0.035\mathrm{}\times {10}^{-24\mathrm{}}$ ${\mathrm{cm}}^2$ for ${\mathrm{S}}^{35}$.