Properties depending on spin-orbit coupling

The so-called heavy-atom chemical shift of light nuclei in nuclear magnetic resonance (NMR) had been identified as a spin-orbit effect early on by Nomura etal. (1969). The theory had been formulated by Pyykktt (1983) and Pyper (1983), and was previously treated in the framework of semi-empirical MO studies (PyykktJ et al. 1987). The basis for the interpretation of these spin-orbit effects in analogy to the Fermi contact mechanism of spin-spin coupling has been discussed by Kaupp et al. (1998b). 

Numerous recent applications have been reported which were carried out either with the all-electron mean-field spin-mbit approach or using pseudopotentials see the recent reviews by Kaupp et al. (1998a) and BUhl etal. (1999). 

The analogy with the Fermi contact interaction predicts particularly large spin-orbit effects when a large-s character of the bonding of the NMR atom to the heavy atom is present. This has been shown—e.g. for the PI cation (Kaupp et al. 1999), 

While this work is based on density-functional theory, recent ab initio work on g tensors comprises contributions from Bruna et al. (1997) and Engstrom et al. (1998). 

In order to test the validity of the inherent approximations in the spin-orbit mean-field and the DFT/MRCI approaches, electronic spectra and transition rates for spin-allowed as well as spin-forbidden radiative processes were determined for two thioketones, namely dithiosuccinimide and pyranthione (Tatchen 1999 Tatchen et al. 2001). In either case absorption and emission spectra as well as depletion rates for the first 

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