Lande g-value

Table I. The Lowest Level of Each Configuration of Pu I and Pu II with their Corresponding Lande g-Values and Experimental Isotope Shifts (E in cm-l and IS in 10-2 cm-l).

The level splitting and with it the frequency shift of the Zeeman line depends on the Lande g values in both levels. For the Ne line X = 3.39 u, for instance, this shift is 1.56 Mc/sec/Gaussfor the ruby line X = 6948 A it amounts to 3 Mc/Gauss, and a total shift of 5 cm has been obtained at 49 KGauss... 

Table 1 Electronic structure and ground-state as well as Lande g values and reduction potentials (vs. SCE) of metallocenes and decamethylmetallocenes as well as their cations, [MCp2] + ...

The Lande g-values for the PB-, PDM-, PTM- and PPF- radicals are about 2.007, 2005, 2.003 and 2.004 respectively. This decrease with the number of a-chlorines suggests the existence of spin-orbit coupling with the chlorine (Ballester et al., 1984c). Accordingly, for a//-decachlorodiphenylmethyls, the value is about 2.003, as in PTM-, and close to the free-electron value. 

Mixing of LS-states by spin orbit coupling will be stronger with an increasing number of f-electrons. As a consequence, intermediate values of Lande g factor and reduced crystal field matrix elements must be used. 

Using the above laboratory relations we compute the values of 6D and 618 expected for rain made by a single distillation from the ocean and for rain made by a subsequent distillation for sea rain which fell on the land. These values show that when rain and snow exhibit very large depletions of the heavy isotopes, e.g., 6D of -200 and -300 ppt, two or three distillations have occurred. It is known from measurements of tritium in rain [76] that two or three distillations occur in the U.S. between evaporation from the Pacific Ocean and precipitation in the eastern U.S. The agreement between the number of distillations deduced from stable isotopes and deduced from tritium is gratifying. 

In the case of cubic symmetry (Fig. la), the px, p 1, and p2 orbitals of the 0 ions would be degenerate, so one is dealing with a 2P state. For zero magnetic field, the 2P state will be split by spin-orbit coupling into two states in which the orbital (L) and spin (S) angular momenta couple (Fig. 2). For small magnetic fields (flH 2, which would apply to normal EPR, since A 135 cm"1), the g value in each level is given by the Lande g factor... 

The factor g in Eqs. 8.14 and 8.15 is a dimensionless quantity called the electron, or Lande g factor (or spectroscopic sphtting factor) and, for the case of a. free electron, it equals precisely 2.0023193. However, it will be seen later that it can have other values when the electron is in condensed matter. 

The parameter g, the Lande g factor, has a value close to 2 for electrons in free space and in practice for most organic radicals. 

Figure 2.15 Transitions observed between a state and P,/2 and states under the anomalous Zeeman effect. Since the Lande g factor gr = 1 + [J J + ) + S S + 1) — Z. (Z. + 1 )]/2 + 1) has a different value in each of these...

The notion of electronic spin was first proposed by Uhlenbeck and Goudsmit in 1925 to account for the sphtting of some of the lines seen in atomic spectra. They and others showed that the electronic spin also accounted for the anomalous effects of magnetic fields (Zeeman effects) on the spectra of many atoms. However, it was necessary to postulate that the magnetic moment associated with electronic spin is not simply the product of the angular momentum and ejlmc, as is true of orbital magnetic moments, but rather twice this value. The extra factor of 2 is called the Lande g factor. When Dirac [33] reformulated quantum mechanics to be consistent... 

Schonland DS. 1959. On the determination of the principal g-values in electron spin resonance. Proa Phys Soc (Land) 73 788-792. 

Since b/a is related to H12/( 11 — H22) and these quantities are comparable in the actinides, the multiply occurring terms can be well mixed (for Pu II f ds P, b/a = 0.66). This will not affect the g-values, since all components have the same Lande g-factor, but it can affect other properties such as the coupling for f-d interactions. 

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