Mossbauer Spectra of Samples with Slow Paramagnetic Relaxation

2 Mossbauer Spectra of Samples with Slow Paramagnetic Relaxation 

Hcf is the crystal field spin Hamiltonian, which can be expressed by (neglecting the fourth order axial term) 

S is the ionic spin and D, ID, and a are crystal field parameters describing the strength of the axial, the rhombohedral, and the cubic crystal field terms, respectively. The coordinate system of the cubic crystal field (ij, rj, g) may differ from that used to describe the axial and the rhombohedral crystal field interactions (x,y,z). 

If an external magnetic field, B, is applied, one has to include the Zeeman Hamiltonian 

The dipole and exchange interactions of an ion, i, with the neighboring magnetic ions, j, can be described by the Hamiltonians Hdd and Hex 

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The crystal field interaction gives rise to an energy splitting into a number of Kramers doublets. In the case of high-spin Fe " with spin S = 5/2, there are three Kramers doublets, each of which give rise to separate contributions in the Mossbauer spectra of samples with slow paramagnetic relaxation. For 1 = 0 and a = 0, they can be labeled l/2), 3/2) and 5/2). 

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