Magnetic anisotropic interactions of nuclei in condensed matter

High-field multinuclear solid-state nuclear magnetic resonance (NMR) and first principle calculations in MgSO4 polymorphs

“…41,42 Thus, one might not necessarily expect an axially symmetric shielding tensor with these restrictions on the principal components of the shielding tensor. 43 Indeed, looking at the shielding asymmetry parameter, η CSA , for 25 Mg in α-MgSO 4 shows a nonaxially symmetric tensor with η CSA = 0.8 ± 0.2. A similar argument can be made for the axially symmetric nature of the EFG tensor.…”

Anisotropy of indirect spin–spin coupling constants from nuclear magnetic resonance powder patterns of rigid solids. 1J(31P,199Hg) in [HgP(o-tolyl)3(NO3)2]2

“…In comparison there are few reliable data on the anisotropy of indirect spin-spin coupling tensors, AJ (9)(10)(11)(12). The experimental determination of indirect coupling anisotropies is complicated because it is generally difficult to separate the anisotropy of the indirect spin-spin coupling from the direct dipolar coupling, D (9)(10)(11)(12).…”

“…The experimental determination of indirect coupling anisotropies is complicated because it is generally difficult to separate the anisotropy of the indirect spin-spin coupling from the direct dipolar coupling, D (9)(10)(11)(12). Also, both theory (13)(14)(15) and experiment (9)(10)(11)(12)(16)(17)(18)(19)(20)(21)(22)(23) indicate that the anisotropy of the indirect coupling is usually small, particularly when the coupling involves only nuclei of low atomic number; this complicates any effort to separate AJ and D.…”

“…Experimentally the anisotropy of J is determined from the nrnr study of oriented molecules in liquid crystalline solvents (9)(10)(11)(12) and from nmr studies of solid powders (16)(17)(18)(19)(20) or single crystals (21)(22)(23). Liquid crystal studies have been most popular; however, the analysis of data is often not straightforward due to complications introduced by solvent and vibrational effects (9)(10)(11)(12).…”

“…Liquid crystal studies have been most popular; however, the analysis of data is often not straightforward due to complications introduced by solvent and vibrational effects (9)(10)(11)(12). The results from single crystal studies are the most reliable, but such studies are tedious and require a large single crystal, which is often unavailable.…”