Spin-orbit coupling value

Figure 4.47. Illustration of triplet harvesting. In the absence of a triplet emitter, the triplet excitation energy is converted to heat, losing 75% of the quantum efficiency. Also shown are a variety of organometallic complexes, and their relative spin-orbit coupling values - directly proportional to their use in phosphorescent OLEDs. Reproduced with permission from Yersin, H. Top. Curr. Chem. 2004, 241, 1. Copyright 2004 Springer Science and Business Media.

Johnson et al. analyzed spin-orbit coupling in phenyl nitrenes (12) using the fidl Breit-Pauli and CASSCF(8,8) wave functions. Within the Cg point group the Tj and Sq states do not couple, and perturbations due to meta substitutions do not increase the spin-orbit coupling value above 0.1 cm. Symmetry allows T to couple with the Sj and S2 states, and the computed values are of the order of 15 cm i for the former and 40 cm for the latter in various para and meta substi-... 

The first theoretical handling of the weak R-T combined with the spin-orbit coupling was carried out by Pople [71]. It represents a generalization of the perturbative approaches by Renner and PL-H. The basis functions are assumed as products of (42) with the eigenfunctions of the spin operator conesponding to values E = 1/2. The spin-orbit contribution to the model Hamiltonian was taken in the phenomenological form (16). It was assumed that both interactions are small compared to the bending vibrational frequency and that both the... 

Owing to the effects of spin-orbit coupling all the triplet terms, except S, are split into three components. For example, in the case of a term, with L = I and S = l,J can take the values 2, 1, 0 (Equation 7.15). 

Figure A The variation with temperature and spin-orbit coupling constant, of the magnetic moments of octahedral, low-spin, d" ions, (The values of at 300 K are marked for individual ions).

As expected, Ap vanishes if the strength of the spin-orbit coupling is reduced to 0 by reducing (co/c) or respectively. Both sets "f model calculations give nearly the same results indicating that the so-called scalar relativistic effects due to the mass-velocity and Darwin-term, are of minor importance for the absolute value of Ap. 

Typical values of g for some sulfonyl radicals are also listed in Table 2. Two main features stand out from these data. First, there is a decrease in the g-value as the electronegativity of the substituents increases, that is, MeSOj (2.0049), Me2NS02 (2.0036), MeOSOj (2.0032) and FSOj (2.0026), and second, there is an increase in the g-value when introducing atoms characterized by large spin-orbit couplings in positions of significant spin density of the radical (cf., for example, entries 7 and 9 as well as 10 and 11 in Table 2). 

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. 

The angular momenta of atoms are described by the quantum numbers L, S or J. When spin-orbit coupling is important, it is the total angular momentum J which is a constant of the system. A group of atomic wavefunctions with a common J value - akin to a term, as described in Section 3.6 - comprise (27 -i- 1) members with Mj... 

Spin-orbit coupling, which arises from the magnetic interactions amongst electrons, splits the F term into levels Fj with J values varying from the sum (L -i-5 ) to the difference IL-51, as usual. We find J ranging 0 to 6 in this case. For less-... 

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