Breaking phenomena molecular approach

The most frequently used single-determinant descriptions of the magnetic systems incorporate spin polarization effects through spin-symmetry breaking of the molecular orbitals. Since the next section is devoted to comparisons between the predictions of the topological approaches and the results of non-empirical calculations, which are performed along the Unrestricted Density Functional Theory (UDFT) approximation, it is worth recalling briefly the main features of the spin polarization phenomenon. 

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