Spin-Hamiltonian operator

The spin Hamiltonian operates only on spin wavefunctions, and all details of the electronic wavefunction are absorbed into the coupling constant a. If we treat the Fermi contact term as a perturbation on the wavefunction theR use of standard perturbation theory gives a first-order energy... 

Appendix G Spin-Hamiltonian Operator with Terms... 

Any set of energetically well-isolated levels can be described by an effective spin Hamiltonian operator by choosing S to match the corresponding number of levels. This can be just one isolated Kramers doublet of a high-spin multiplet if the... 

Schematically, the double exchange interaction can be written in the form of a spin Hamiltonian operator (working on the system spin AB —for short, S) as...

The spin-Hamiltonian operator can be written as the sum of a large number of terms for example, see Equation (A3) in Appendix 3. As may be seen therein, the convention for the two Zeeman terms (electron spin and nuclear spin) is that their signs differ, due to the difference in charge of the two most basic particles to be dealt with the electron and the proton. Hence the g values of these particles are taken to be both positive. 

A basic reason for existence of the above-stated problem is that the parameters cited are linked to quantum-mechanical angular-momentum (spin) operators, for instance via the usual spin-Hamiltonian operator... 

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