Magnetic fields diamagnetic contribution

Fig. 7 Temperature dependence of the static magnetic susceptibility of (a) (EDT-TTFBr2)2 FeBr4 (b) (EDO-TTFBr2)2FeCl4 (c) (EDO-TTFBr2)2FeBr4 measured at an external field of B = 1 T after the core diamagnetic contributions are subtracted...

The diamagnetic contribution to the shielding tensors can be defined as the derivative of this Hamiltonian with respect to the magnetic moment Uk=YkIk of nucleus K and the external magnetic field... 

The magnetic hyperfine field (Bhf) decreases as structural Al increases. This is to be expected because the diamagnetic Al does not contribute to the magnetic field. Since, however, Bhf (T) is also reduced as the crystal size decreases (even at 4 K), both Al substitution and crystal size (here represented by mean coherence length perpendicular to (111), MCLm, in nm) must be combined to account for the variation of Bhf satisfactorily, (Schwertmann Murad, 1983) i.e. 

Chemical shifts, as treated by Ramsey (113), are comprised of separate diamagnetic and paramagnetic contributions. The diamagnetic term was considered to arise from the response of the extranuclear electrons to the external magnetic field and had been given earlier by Lamb (65) as... 

The diamagnetic contribution follows from Larmor s theorem (389) which states (For a proof of this theorem, see reference (028), p. 22.) For an atom in a magnetic field, the motion of the electrons isf to a first approximation in H, the same as a motion in the absence of H except for the superposition of a common precession of angular frequency u)L = ell/2mc = IIp.fi/ti. The angular momentum of an atom is, from equation 7 ... 

---