Wood-Boring operator

In the Cowan-Griffin-Wood-Boring Hamiltonian, the 7] and operators of Eq. (4) read ... 

The coefficients and exponents are fitted to the radial components of the Wood-Boring spin-orbit operator, or some other suitable spin-orbit operator. 

The deficiencies of this procedure have been carefully analysed by Boring and Wood [62] who worked with an approximate treatment of the Dirac equations, due to Cowan and Griffith [63]. In this method the spin-orbit operator is omitted from the one-electron Hamiltonian but the mass-velocity... 

If we want to incorporate spin-orbit effects, either subsequent to a spin-free relativistic calculation using this operator or directly as a first step using a modified operator, we must include the previously discarded last term of the large component of the Dirac equation above. For atoms, this was first done by Wood and Boring (1978), who used the operator perturbatively. 

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