Lanthanide ions spin-orbit coupling

Again, however, this is strictly applicable only for free ions. Even though spin-orbit coupling is much less important for the first row of the d block, this formula provides a far less good approximation for d -block complexes than Eq. (5.6) does for lanthanide complexes. The reason is that the ground, and other, terms in these d complexes differ grossly from those of the corresponding free ion. These differences are one result of the crystal field. 

The spin—orbit coupling constants f4f and fsd, which represent the relativistic spin—orbit interaction in the 4f and 5d shells, also determined by means of the radial wave functions Rrd of the 4f and 5d Kohn—Sham orbitals of the lanthanide ions.23... 

All lanthanide ions, with the exception of gadolinium(III) and europium(II), are likely to be relaxed by Orbach-type processes at room temperature. In fact, the f" configurations n l) of lanthanides(III) give rise to several free-ion terms that upon strong spin-orbit coupling, provide several closely spaced energy levels. Table III reports the multiplicity of the ground levels, which varies from 6 to 17, and is further split by crystal field effects. 

In the lanthanide series, we have 14 elements that result from the addition of electrons into the f orbitals. For the lanthanide series, the electron configurations are 4f (1—14). In the lanthanide series, the majority of the compounds are formed by trivalent M3+ ions. From a spectroscopic point of view, all the rare earth ions have a large spin-orbit coupling constants, resulting in electronic states being defined by the angular momentum... 

I is the spin-orbit coupling constant which ranges from 600 to 3000 cm throughout the lanthanide series, the highest values corresponding to the heaviest lanthanide ions. 

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