The effects of partial orientation

Changes in contact shifts may as well be expected as (Sz) is not isotropic (see Section 2.2.1) [57], but this research area is not yet explored. Self orientation, instead, is conveniently measured as variation of lJ 15N- H or 2J in H- N- H systems as a function of the extent of the orientation, i.e. as a function of the magnetic field [58,59] (see Section 2.10)  

From the lJ residual dipolar coupling the molecular magnetic anisotropy tensor is obtained, which differs from the metal contribution by an extent which depends on the magnetic anisotropy of the diamagnetic part. For example, in cytochrome b the diamagnetic, the paramagnetic and the total susceptibility anisotropy values are A Xax = —0.8, 2.8, 2.20 x 10 32 m3, respectively, and Axrh = 0.1, —1.1, — 1.34 x 10-32 m3, respectively [60]. The corresponding tensors sum up as expected. 

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