Effect of Anisotropic Hyperfine Interactions on Paramagnetic Relaxation in Liquids

摘要

A simple ``microcrystalline model'' is developed to discuss the effect of molecular motion in the liquid state on the paramagnetic relaxation of ions or molecules with spinS= frac12;. This theory relates the paramagnetic relaxation timesT1andT2prime; to the anisotropy ing,Dgr;g=gIImdash;gperp;, to the anisotropy in the nuclear hyperfine interaction,Asngbnd;B, and to the correlation time tgr;cwhich describes the Brownian tumbling motion of the microcrystal in the liquid state. The contribution of the anisotropic hyperfine interaction to the paramagnetic relaxation turns out to depend on the nuclear spin quantum numberIz, so that different hyperfine multiplets in a paramagnetic resonance spectrum can show different line widths.