Bonner—Fisher method

The Bonner-Fisher method has been extended to an infinite chain of S = 1 centres by Weng, valid for / < 0 and applied by Kahn to the problem of modelling the behaviour of [Ni(N02)(en)]X, where X = C104 or... 

The magnetic properties of M2VF5 phases (M = K, Rb, Cs) have been studied by Padalko et al.197). The intrachain exchange constants have been calculated by means of the Bonner and Fisher method applied to 1-D Heisenberg spin lattices (Table 10) using the formula ... 

Equation 3.25 makes the explicit assumption that it is reasonable to ignore anisotropy, that is that the zero-field splitting, IDI << l/l. It is possible to perform numerical calculations that take D into account, but these are probably of limited usefulness when trying to model real data. The Bonner and Fisher method becomes computationally difficult for S > 1 if the spin is treated as a quantum mechanical quantity. In the limit of large S, however, the spin can be treated as a classical quantity. Perhaps somewhat surprisingly, such a treatment works reasonably well for values of S as small as 5/2. Such a system can be synthetically realised with a chain of Mn, which has an isotropic ground state. Fisher has derived an expression for an infinite chain of classical spins, scaled to a quantum spin,... 

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