NMR Relaxation Times in Solid White Phosphorus: Diffusion and Rotation

Abstract

Nuclear magnetic resonance relaxation times have been measured for solid white phosphorus by spin‐echo techniques. The diffusion coefficient calculated from T₂ in the α phase can be represented as $${\mathrm{D=D}}_0\exp \mathrm{(-\Delta H/RT),}$$ where D₀=0.077±0.014 cm²/sec, and ΔH=12.1±0.1 kcal/mole. The correlation time for rotation calculated from T₁ in the β phase can be represented by $$t_c{\mathrm{=t}}_0\exp \mathrm{(\Delta H/RT),}$$ where t₀=6.04×10^—14 sec, and ΔH=4.02±0.02 kcal/mole. The distance between phosphorus atoms in the P₄ molecule is found to be 2.24±0.03 Å from the value of T₁ at the T₁ minimum in the β phase.