Quantum chemical methods shielding tensor

The m.p. line-narrowing technique has added an impressively long list of proton shielding tensors a to our knowledge of material properties. Complementary access to such tensors is to calculate them by quantum chemical methods. An important advantage of this approach is that, in addition to the symmetric constituent of a, it also yields the components of the antisymmetric constituent o " that are virtually inaccessible to measurements by spectroscopic means. So far only relaxation studies have provided experimental information about (Kuhn, 1983 Anet and O Leary, 1992). Note that these experiments were done on carbons. 

The determination of the NMR chemical shift or chemical shielding anisotropy (CSA) tensor from quantum mechanical methods remains a crucial... 

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