Orbital momentum quenching

Although we have treated the hyperfine interaction as an interaction between the nuclear spin I and the intrinsic spin s of the electron, it is in reality the interaction of I with the total angular momentum of the electron. Most lanthanide and actinide ions and some transition metal ions in high symmetry do not have their orbital momentum quenched by the crystal fields. In these cases a complete treatment of the hyperfine interaction must include the following term... 

Optical recording systems, 6, 126 Optical resolution amine metal complexes, 2,25 Oral contraceptives iron deficiency, 6, 764 Orbital angular momentum quenching, 1,262 /-Orbital systems... 

This is known as the spin-only formula. Many ions which in the free state have orbital angular momentum L 0), lose it, completely or partially, when incorporated into a complex. This phenomenon is called orbital angular momentum quenching. It can be shown that for A states the quenching is complete and that for T and E states it is incomplete. Because of this, the spin-only formula applies to more situations than might have been expected. 

If the orbital momentum is completely quenched (spin-only magnetism), the Curie constant can be derived from the total spin quantum number S ... 

Since the Ti /H2C>2 reduction is an important system for producing OH radicals and has been used for many studies involving alcohols, it is perhaps interesting to note some of the ESR properties of the Ti+++ ion. The aqueous Ti+++ ion is believed to be coordinated as Ti(H2O)g and has no observable ESR spectrum because of the very short relaxation time. However, if the symmetry is reduced to tetragonal or lower, the orbital momentum should be completely quenched and a narrow ESR line is expected. This phenomenon has been observed in water-alcohol solutions (157). Recently Bolton and coworkers (158) have further observed some proton hyperfine structure from the water ligands of the aqueous Ti+++ complex in a 20% butyl alcohol-water solution. There has been a standing controversy in the interpretation of the spectra detected in the Ti(Il I), Ti(IV)-H2C>2 system (159-162). 

Quenching of the Orbital Angular Momentum As electrons will have orbital momentum around the given axis (say az-axis), if the orbital that it occupies can be transformed into an entirely equivalent orbital (which should be degenerate also with it) by a simple rotation around the axis. The electron in the d2 -... 

The fact that the calculated magnetic moment assuming only spin orbital momentum for the isolated cations of the 3d transition series compares favorably with the experimentally determined values (see Table 15.2) implies that the orbital angular momentum for these ions is indeed quenched. 

Orbital angular momentum quenching, 262 /-Orbital systems... 

The very first laser, the ruby laser, belongs to the family of the transition metal ion lasers. However, its wavelength is fixed.Its lower lasing state is the ground state, the orbital momentum of which is quenched by the crystal field. There is no direct coupling of the lattice vibrations to this ground state, i.e. no phonon sideband can occur. 

In the case of alexandrite, the model example of a tunable transition metal ion laser, the crystal field does not quench the orbital momentum of the and lattice... 

Because of the spin-space geminal-space isomorphism found in the simple model, consideration of the behavior of the energies and the wave functions runs along completely parallel tracks in the two cases. This includes the identification of conditions under which the lowest two states are degenerate, of particular interest for photochemistry. Phenomena such as "sudden polarization" and "orbital angular momentum quenching" all fit into a single picture. 

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