Spin states magnetic properties

Rubidium gas has become important in the study of an exotic state of matter called a Bose-Einstein condensate. This state, first predicted in 1924 by Indian physicist Satyendra Nath Bose, was not observed until 1995. Many laboratories now produce these cooled clouds of atoms, mostly using gases of alkali elements, which have appropriate spin and magnetic properties. 

MCD spectra can profitably separate contributions from multiple metal centres to a protein electronic spectrum, be used to evaluate metallo-biological systems without complications from the protein milieu , determine zero-field splitting, assign electronic transitions, provide information about a chromophore s electronic structure, evaluate theoretical models, obtain magnetic properties (g values, spin states, magnetic coupling) and be used for structural comparison of model and biological systems. 

The negative sign in equation (b 1.15.26) implies that, unlike the case for electron spins, states with larger magnetic quantum number have smaller energy for g O. In contrast to the g-value in EPR experiments, g is an inlierent property of the nucleus. NMR resonances are not easily detected in paramagnetic systems because of sensitivity problems and increased linewidths caused by the presence of unpaired electron spins. 

The magnitude of the separation between the adjacent states of a term indicates the strength of the spin-orbit coupling, and in all but two cases (Sm and Eu ) it is sufficient to render the first excited state of the Ln ions thermally inaccessible, and so the magnetic properties are determined solely by the ground state. It can be shown that the magnetic moment expected for such a situation is given by ... 

From the selection rules of the 6j coefficients (.89), it follows that the biquadratic terms cannot mix the S = I levels with higher spin states. By contrast, the anisotropic symmetric and antisymmetric terms, whose magnitude is related to that of the isotropic component (89), can give rise to a substantial mixing. However, a detailed quantitative model is needed to verify whether the peculiar magnetic properties of [3Fe-4S] + centers can be explained by this mixing. 

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