Nuclear magnetic resonance in solid and liquid manganese

Nuclear-magnetic-resonance measurements at elevated temperatures are described for the four solid allotropic forms and the liquid state of manganese. Knight-shift ($\mathcal{K}$) data extend from 300 K ($\alpha -\mathrm{M}\mathrm{n}$) to 1575 K (liquid) and spin-lattice relaxation rates ($\frac{1}{T_1}$) were measured from 1050 K ($\beta -\mathrm{M}\mathrm{n}$) to 1570 K (liquid). Knight shifts in $\alpha -$ and $\beta -\mathrm{M}\mathrm{n}$ exhibit a strong dependence on crystallographic site reflecting a highly nonuniform distribution of paramagnetism within the unit cell. Motional narrowing of the splitting between the two inequivalent sites in $\beta -\mathrm{M}\mathrm{n}$ allowed determination of $\mathcal{K}$ for both sites. At 1200 K, ${\mathcal{K}}_{\mathrm{I}}=(+0.030\mathrm{}\pm 0.005)\%$ and ${\mathcal{K}}_{\mathrm{II}}=(-0.720\mathrm{}\pm 0.005)\%$ for type-I and type-II sites, respectively. In contrast to $\alpha -$ and $\beta -\mathrm{M}\mathrm{n}$, small changes of $\mathcal{K}$ and $\frac{1}{T_1}$ at the high-temperature transitions indicate that the $d-\mathrm{s}\mathrm{p}\mathrm{i}\mathrm{n}$ magnetization is only weakly influenced by crystal structure changes at high temperature and by melting. The observed shifts are (-0.690 ± 0.005)% ($\gamma -\mathrm{M}\mathrm{n}$ at 1400 K), (-0.828 ± 0.005)% ($\delta -\mathrm{M}\mathrm{n}$ at 1450 K), and (-0.821 ± 0.005)% (liquid Mn at 1525 K). With the exception of shifts for type-I and type-II sites in $\alpha -\mathrm{M}\mathrm{n}$, all shifts tend toward more negative values with increasing temperature within a single phase region. Above 1375 K, ${\left(T_{1}T\right)}^{-1\mathrm{}}$ is essentially constant in $\gamma -$, $\delta -$, and liquid Mn and equal to 14.5 ± 0.7 ${\mathrm{}\left(\sec \mathrm{K}\right)\mathrm{}}^{-1\mathrm{}}$. Decomposition of the $d$-spin susceptibility using a $\mathcal{K}$ vs $\chi$ analysis led to orbital and spin susceptibilities of (0.141 ± 0.017) × ${10}^{-3\mathrm{}}$ and (0.451 ± 0.017) × ${10}^{-3\mathrm{}}$ emu/mole for $\gamma -\mathrm{M}\mathrm{n}$, and similar values were obtained for