Lanthanides ground levels

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. 

Martin, W. C. Hagan, L. Reader, J. and Sugar, J., "Ground levels and ionization potentials for lanthanide and actinide atoms and ions," Jj Phys. Chem. Ref. Data, 1974, 771-780. 

For ground levels of some lanthanide ions the sums in (20) can be reduced to a single term. Thus for Ho 4f l8 we have... 

Tables 1.13a and 1.13b comprise the ground levels and ionization potentials of the neutral through triply ionized lanthanides (Martin et al., 1974).

Ground levels and ionization potentials for the neutral and singly ionized lanthanide atoms. The designation of the ground level of Tb 11 is enclosed in braces because the indicated level has not yet been experimentally established as lowest. , ... 

The enthalpies of atomization were calculated from the appearance energies AE(R" /RCl2) using the ionization energies of lanthanides recommended by the National Institute of Sfandards (USA) (NIST Ground Levels). Their recalculation from 0 to 298 K and calculations of AsubH°(298) from the enthalpies of atomization (see Table 61) were... 

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