Spin-orbit coupling indirect

This term is important only in that it gives a second-order contribution to the hyperfine interaction by allowing the nuclear spin and electron spin to couple indirectly through the orbital momentum. 

Fig. 13 Illustration of indirect spin-orbit coupling in a 3-state model. The 3LC substate 3(ti7t )+1 can mix via configuration interaction (Cl) with the 3MLCT substate 3(d7t )+1, which contains admixtures of the higher lying MLCT state Xd Tt ) via SOC...

However, relativistic effects have a much more profound influence on a material s properties. Thus, the existence of a spin quantum number allows for the existence of magnetism. Moreover, as shown in most standard textbooks on physical chemistry, the phenomenon of phosphorescence can only be explained through the existence of relativistic effects. Phosphorescence involves transitions between, for example, singlet and triplet states which are only possible if some spin-operating effects exist, e.g. spin-orbit couplings. Furthermore, several experimental techniques are indirectly based on exploiting relativistic effects. These include, for example, electron-spin and NMR spectroscopies. 

The method works as follows. The mass velocity, Darwin and spin-orbit coupling operators are applied as a perturbation on the non-relativistic molecular wave-functions. The redistribution of charge is then used to compute revised Coulomb and exchange potentials. The corrections to the non-relativistic potentials are then included as part of the relativistic perturbation. This correction is split into a core correction, and a valence electron correction. The former is taken from atomic calculations, and a frozen core approximation is applied, while the latter is determined self-consistently. In this way the valence electrons are subject to the direct influence of the relativistic Hamiltonian and the indirect effects arising from the potential correction terms, which of course mainly arise from the core contraction. 

The fine structure constant A was determined indirectly from the perturbations by the riy state of the observed Zeeman shifts in the state, A= -177.3 5.6 cm" [2]. A splitting of 160 30 cm was derived from an asymmetry of the vibrational components of three photoelectron bands [1]. A = ( )188cm was calculated from the atomic spin-orbit coupling constants and from the F hyperfine coupling constant [2]. The method used was described in... 

An indirect mode of anisotropic hyperfine interaction arises as a result of strong spin-orbit interaction (174)- Nuclear and electron spin magnetic moments are coupled to each other because both are coupled to the orbital magnetic moment. The Hamiltonian is... 

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