Magnetic Hamiltonian with electron and nuclear spins

6 INCLUSION OF THE ELECTRON AND NUCLEAR SPINS 3.6.1 Magnetic Hamiltonian with electron and nuclear spins 

In the third, the most general case the energy of the system depends upon the external magnetic field, the magnetic moments of nuclei and the electronic magnetic moment. The following expansion of the magnetic Hamiltonian is assumed 

Here we have included also the Hamiltonian terms not mentioned before but following from the relativistic approach the spin-spin contact interaction and the spin-spin dipolar interaction terms contained in and the 

Fermi contact interaction and the dipolar hyperfine interaction contained in 

The spin-spin contact and dipolar terms arise from the interaction between the electronic magnetic moment and the internal magnetic field generated by the other electron at the position of the first electron 

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